How to Wash a Foam Mattress: Complete Cleaning Guide

You cannot machine wash or submerge a foam mattress in water. The correct way to wash a foam mattress is to spot clean stains with a mild detergent solution, baking soda, or an enzyme-based cleaner, then allow the mattress to air dry completely before putting sheets back on. Soaking a memory foam mattress or putting it in a washing machine will break down its internal cell structure, permanently ruining the support it provides. The cleaning method varies slightly depending on whether you are dealing with a fresh spill, a set stain, or general odor buildup — and this guide walks through each scenario in detail.

Why You Should Never Submerge a Memory Foam Mattress in Water

Memory foam mattresses are made from viscoelastic polyurethane foam, a material that responds to body heat and pressure to conform to your shape. That same open-cell structure that makes memory foam so comfortable also makes it extremely absorbent. When fully saturated, a queen-size memory foam mattress can hold several gallons of water — and most of that moisture gets trapped deep inside layers that no fan or towel can reach.

If the interior of the mattress stays damp for more than 24 to 48 hours, mold and mildew begin to grow. Mold colonies can establish themselves inside foam within 24–48 hours of sustained moisture exposure, and once mold takes hold inside a foam core, there is no practical way to remove it without destroying the mattress. The foam also degrades when waterlogged, causing it to tear, crumble, or lose its density — which shortens the lifespan of what is typically a $500–$2,000+ investment.

Even running a memory foam mattress through a spin cycle in a washing machine — even a large front-loader — applies mechanical forces the foam is not designed to withstand. The agitation tears apart the foam cells, and you will end up with a lumpy, structurally compromised mattress that no longer supports proper spinal alignment.

What You Will Need Before You Start Cleaning

Gathering everything beforehand makes the process smoother and reduces the risk of over-wetting the foam while you search for supplies. Here is what to have on hand:

• Cold or lukewarm water (never hot — heat can distort foam and set protein-based stains like blood)
• Mild liquid dish soap or upholstery cleaner
• Baking soda (sodium bicarbonate) — a box is enough for a full mattress surface
• White vinegar (distilled, not apple cider) in a spray bottle
• Enzyme-based cleaner (essential for urine, blood, sweat, or vomit stains)
• Clean white cloths or microfiber towels — avoid colored cloths that could transfer dye
• A vacuum cleaner with an upholstery attachment
• A fan or access to a well-ventilated area with sunlight

Do not use bleach, hydrogen peroxide in high concentrations, or harsh chemical solvents on memory foam. Bleach breaks down foam polymers and can leave the surface brittle or discolored. Hydrogen peroxide above 3% concentration has a similar degrading effect on the foam structure over time.

Step-by-Step: How to Spot Clean a Memory Foam Mattress

Spot cleaning is the correct technique for isolated stains — a spilled drink, a blood spot, a pet accident in one area. The goal is to clean the surface without pushing moisture deeper into the foam. Speed matters: the sooner you treat a stain, the easier it is to remove.

Step 1 — Strip the Bedding and Remove the Mattress Cover

Remove all sheets, pillowcases, and the mattress protector. If your memory foam mattress has a zippered cover, unzip it and toss it in the washing machine on a gentle cycle — most covers are machine washable, though always check the care tag. Washing the cover separately is much easier and more effective than trying to clean everything in one pass.

Step 2 — Blot, Never Rub

For any liquid stain, use a clean dry cloth to blot up as much moisture as possible before applying any cleaning solution. Press firmly and lift straight up — rubbing spreads the stain and pushes it deeper into the foam. Work from the outside edges of the stain toward the center to prevent it from spreading outward.

Step 3 — Apply a Mild Cleaning Solution

Mix one teaspoon of mild liquid dish soap with one cup of cold water. Dampen (do not soak) a clean cloth with this solution, then dab it onto the stain. The cloth should be moist, not dripping — squeeze out any excess liquid before it touches the foam. Work in small circular motions, applying light pressure.

For a stronger but still foam-safe cleaning solution, combine equal parts white vinegar and cold water in a spray bottle. Mist the stained area lightly, wait two minutes, then blot with a dry cloth. The acetic acid in vinegar breaks down many common stains and also acts as a mild deodorizer.

Step 4 — Rinse Without Over-Wetting

Use a separate cloth dampened with plain cold water to blot away any soap residue. Soap left in the foam can attract dirt over time and leave the surface slightly sticky. Again, use a damp cloth — not a wet one. Repeat blotting with a dry towel until no more moisture transfers to the towel.

Step 5 — Apply Baking Soda and Let It Sit

Sprinkle a generous layer of baking soda over the cleaned area (and across the whole mattress surface if you want a general refresh). Baking soda absorbs residual moisture and neutralizes odors. Leave it on for a minimum of 8 hours — overnight is better, and 24 hours is ideal. The longer it sits, the more effective it is at pulling out trapped moisture and odors from deeper layers.

Step 6 — Vacuum Up the Baking Soda

Use the upholstery attachment on your vacuum cleaner to thoroughly remove all the baking soda. Go over the surface twice in different directions to make sure nothing is left behind. Then allow the mattress to finish air drying before replacing any bedding.

How to Remove Specific Stains from a Memory Foam Mattress

Different stains respond to different cleaning agents. Using the wrong one can set the stain permanently or damage the foam. The table below summarizes the best approach for each common stain type.

Removing Urine from a Memory Foam Mattress

Urine is one of the most common and most challenging foam mattress stains because it contains uric acid crystals that bind to foam and continue to emit odor even after surface cleaning. A standard dish soap solution will clean the visible stain but will not neutralize the uric acid. An enzyme-based cleaner is essential for urine — it contains biological enzymes that literally break down the uric acid molecules, eliminating both the stain and the odor at the source.

For fresh urine: blot up as much liquid as possible immediately, apply enzyme cleaner according to the product instructions, cover the area with a damp cloth to keep it moist while the enzymes work (usually 10–15 minutes), then blot dry and apply baking soda for 8+ hours before vacuuming. For dried urine: lightly mist the area with cold water to reactivate it slightly before applying the enzyme cleaner.

Removing Blood Stains from a Memory Foam Mattress

Cold water is non-negotiable when dealing with blood. Blood contains hemoglobin, a protein that denatures (permanently bonds) when exposed to heat. Even lukewarm water can make a blood stain significantly harder to remove. For fresh blood, blotting with a cloth dampened in cold water and a few drops of dish soap is usually sufficient. For dried blood that has had time to set, apply a small amount of 3% hydrogen peroxide (available at any pharmacy) directly to the stain. It will bubble as it reacts with the hemoglobin — that reaction is breaking down the stain. Blot away after 2–3 minutes, then follow with plain cold water and dry thoroughly. Do not let hydrogen peroxide sit on the foam for extended periods.

How to Deep Clean an Entire Memory Foam Mattress

A full deep clean is worth doing every 3–6 months, even without visible stains. Over time, a memory foam mattress accumulates sweat, dead skin cells, dust mites, and body oils that degrade the foam and affect sleep hygiene. The process is more involved than spot cleaning, but the principle is the same — use as little moisture as possible and ensure complete drying before use.

1. Vacuum the entire surface — use the upholstery attachment to go over the top, sides, and bottom of the mattress. This removes loose debris, dust mite waste, and dead skin cells before any moisture is introduced.
2. Deodorize with baking soda — sprinkle a generous, even layer of baking soda across the entire top surface. For extra odor-fighting power, mix a few drops of essential oil (lavender or tea tree are popular choices) into the baking soda before applying. Leave for a minimum of 8 hours.
3. Vacuum up the baking soda — go over the surface thoroughly in multiple passes to remove all residue.
4. Address any remaining stains — using the spot cleaning method described above, treat individual stains after the baking soda step.
5. Allow complete air drying — prop the mattress on its side if possible to allow airflow on both faces, or place it near an open window or fan. Never replace bedding until you are certain the mattress is fully dry.
6. Flip or rotate — most memory foam mattresses should not be flipped (as they have a top layer and base layer with different densities) but should be rotated 180 degrees to distribute wear evenly. Check the manufacturer's guidance for your specific mattress.

How to Dry a Foam Mattress Properly — and Why It Matters So Much

Drying is the most critical and most commonly mishandled step. Many people clean their mattress well but then put their sheets back on within a few hours, trapping residual moisture and creating exactly the mold-friendly environment they were trying to avoid. A foam mattress should be completely dry before any bedding is placed on it — and that can take anywhere from 2 to 8 hours for surface drying, and up to 24 hours if more moisture was applied.

Air Drying with a Fan

Place a standing or box fan 12–18 inches from the cleaned area and set it to medium or high. Airflow accelerates evaporation from the surface. If cleaning the whole mattress, prop it vertically against a wall to expose both sides to airflow simultaneously. Open windows in the room to encourage fresh air circulation.

Sunlight and Natural Ventilation

On a dry, sunny day, moving the mattress outdoors to dry in direct sunlight is highly effective. Sunlight has the added benefit of killing bacteria and dust mites — UV radiation is naturally antimicrobial. Even 2–3 hours of direct sun exposure significantly reduces microbial load on the foam surface. Make sure to bring the mattress back inside before evening humidity rises.

What Not to Do When Drying

• Do not use a hair dryer on high heat — concentrated heat can melt or distort foam cell structure
• Do not put foam mattresses in a clothes dryer, even on a no-heat cycle
• Do not leave the mattress in a humid room — this slows evaporation and encourages mold
• Do not cover the mattress with sheets or blankets to speed up drying — they trap moisture

If you are unsure whether the mattress is fully dry, press your hand firmly into the area that was cleaned and hold it for 10 seconds. If you feel any coolness, dampness, or detect a faint musty smell, it needs more drying time.

How to Clean a Memory Foam Mattress Topper

A memory foam mattress topper follows the same cleaning rules as a full mattress, but it is easier to manage because of its size and lighter weight. Most toppers are 2–4 inches thick, which means moisture penetrates more easily — use even less liquid than you would on a full mattress, and drying time is typically shorter.

One option that full mattresses do not have: if your topper is small enough, you can take it into a bathtub for spot cleaning. Use the showerhead on a gentle setting to rinse a specific area (not to soak the whole topper), then press firmly with dry towels to extract as much water as possible before air drying. Even then, do not wring or twist a foam topper — this tears the foam structure.

After cleaning, hang the topper over a shower rod, a porch railing, or a drying rack to allow both surfaces to air out simultaneously. A topper that is 2 inches thick may be fully dry in 3–4 hours; a 4-inch topper may need closer to 8–12 hours.

How Often Should You Clean a Memory Foam Mattress?

Most people clean their mattress far less often than they should. Dermatologists estimate that the average person sheds about 30,000–40,000 dead skin cells per hour while sleeping, and a typical mattress can harbor anywhere from 100,000 to 10 million dust mites depending on cleaning habits and climate. This accumulation happens regardless of whether visible stains are present.

How to Protect a Memory Foam Mattress and Reduce How Often It Needs Cleaning

Prevention is far easier than remediation when it comes to foam mattresses. The single most impactful thing you can do is use a high-quality waterproof mattress protector. A waterproof mattress protector can extend the usable lifespan of a memory foam mattress by several years by preventing moisture, sweat, and spills from ever reaching the foam.

When shopping for a mattress protector, look for one that is:

• Waterproof on the underside (polyurethane laminate is common) but breathable on the surface — otherwise heat buildup can cause sweating, which creates the moisture problem you were trying to avoid
• Machine washable and dryer-safe for easy maintenance
• Fitted with a deep pocket or zippered encasement design to prevent it from sliding during sleep
• Hypoallergenic if dust mites are a concern for anyone in the household

Additional habits that reduce mattress soiling include: not eating or drinking in bed, keeping pets off the mattress, showering before sleep if you have been sweating heavily, and ensuring the bedroom has adequate ventilation to reduce ambient humidity. In very humid climates, running a dehumidifier in the bedroom can meaningfully reduce moisture accumulation in the mattress over time.

Signs Your Memory Foam Mattress Is Beyond Cleaning

Cleaning has limits. If a memory foam mattress has been severely neglected or has experienced significant water damage, cleaning will not restore it to a safe or comfortable state. Here are the signs that replacement is the more practical choice:

• Visible mold growth — black, green, or white patches that reappear even after surface cleaning indicate mold has colonized the interior foam, which cannot be safely remediated at home
• Persistent musty odor after thorough drying and multiple baking soda treatments — this typically indicates deep mold or bacterial growth
• Body impressions deeper than 1.5 inches that do not recover — this indicates foam degradation unrelated to cleanliness, but if cleaning revealed or accelerated the problem, it signals the foam has broken down
• Allergic reactions or worsening asthma despite cleaning — if occupants are reacting to the mattress, mold or dust mite infestation may be too extensive to fully address with surface cleaning
• Age over 8–10 years — most quality memory foam mattresses have a lifespan of 8–10 years, after which the foam loses its supportive properties regardless of how well it has been maintained

If any of these conditions apply, continuing to sleep on the mattress poses real health risks. Mold exposure is associated with respiratory problems, skin irritation, and immune system effects. At that point, replacement is the medically and practically sound decision.

Frequently Asked Questions About Washing Foam Mattresses

Can you use a steam cleaner on a memory foam mattress?

Steam cleaning is generally not recommended for memory foam. The combination of heat and moisture that steam produces can penetrate deep into the foam, and the heat can distort the foam's cell structure. Some manufacturers specifically warn against steam cleaning in their care instructions. There are professional mattress cleaning services that use low-moisture foam cleaning systems specifically designed for memory foam — those are a safer alternative if you want a more thorough clean than DIY methods provide.

Can you use Febreze or fabric spray on a memory foam mattress?

Febreze and similar fabric refreshers are generally safe to use lightly on a memory foam mattress surface, but they should be used sparingly. They contain alcohol and other compounds that can, over many repeated applications, degrade the surface of the foam. They also mask odors rather than eliminating them — baking soda actually absorbs and neutralizes odor molecules rather than covering them up. Use fabric sprays occasionally, not as a substitute for proper cleaning.

How long does it take for a memory foam mattress to dry after cleaning?

Drying time depends heavily on how much moisture was applied, the ambient temperature and humidity, and whether airflow is being used. For a minimal spot clean where the cloth was barely damp, the area may be dry in 1–2 hours with a fan running. For more aggressive cleaning where more liquid was used, plan for 6–12 hours of drying time. When in doubt, give it longer — a completely dry mattress is always worth the extra wait.

Does cleaning affect the memory foam's ability to respond to body heat?

When cleaned correctly — using minimal moisture and gentle agents — the foam's viscoelastic properties are not significantly affected. The temperature-sensitivity that allows memory foam to soften and conform is a property of the polymer chains within the foam, not the surface. However, using harsh chemicals, excessive heat, or soaking the foam can permanently alter those polymer chains, reducing the foam's responsiveness and comfort.