A mattress absorbs a lot over the years: sweat, body oils, spills, pet accidents and humidity. Eventually some of that turns into a smell you notice every time you strip the sheets. The good news is that most mattress odors can be removed at home with a vacuum, baking soda, an enzyme cleaner and plenty of air and sunlight. This guide walks through the process, explains how to handle specific smells like sweat, vomit, pet urine and mildew, and tells you when an odor means it is time to replace the mattress.
One note before you start: if the smell is a chemical odor from a brand new mattress, that is off-gassing, not dirt, and it needs a different approach. See our guide to new mattress smell and off-gassing.
What you will need
- A vacuum with an upholstery attachment
- Baking soda (a full box for a queen or king)
- An enzyme cleaner made for pet or organic stains
- White vinegar and a spray bottle
- Mild dish soap
- Clean white cloths or paper towels
- A fan, and ideally a sunny window or a spot outdoors
Step 1: Strip the bed and wash everything
Remove sheets, pillowcases, the mattress protector and any mattress pad, and wash them in the hottest water the care labels allow. Odors often live in bedding as much as in the mattress, and there is no point deodorizing the mattress only to put a smelly protector back on it.
Step 2: Find the source
Sniff the mattress section by section. A localized smell usually points to a spill or accident, while an all-over musty smell usually means built-up sweat or humidity. Look for stains, discoloration or dark spots, which can indicate mildew. Treating the specific cause works far better than masking the whole surface.
Step 3: Vacuum thoroughly
Vacuum the entire top surface, the sides and the seams with an upholstery attachment. This lifts dust, dead skin and debris that hold odor, and it gives the cleaning steps that follow better contact with the fabric.
Step 4: Spot-treat odor sources
For organic smells such as sweat, urine or vomit, an enzyme cleaner is the most effective tool. Enzymes break down the proteins and compounds that cause the smell instead of covering them up.
- Blot up any fresh moisture first. Press, do not rub.
- Lightly mist the area with enzyme cleaner. Do not soak it; foam layers hold moisture and dry slowly.
- Let it sit for the time on the label, usually 10 to 15 minutes or longer.
- Blot with a clean cloth to lift the cleaner and the residue.
If you do not have an enzyme cleaner, a light mist of equal parts white vinegar and water, followed by blotting, helps neutralize many odors. The vinegar smell fades as it dries.
Step 5: Deodorize with baking soda
Once any damp spots are only slightly moist, sprinkle an even layer of baking soda over the whole mattress, concentrating on problem areas. Baking soda absorbs moisture and odor. Leave it for at least several hours; overnight or a full day works best for stubborn smells. Then vacuum it up completely.
Step 6: Air it out and let it dry completely
Air and sunlight are underrated odor removers. Open windows, run a fan across the mattress and, if you can, stand it in indirect sunlight for a few hours. Southern California's dry, sunny weather is an advantage here; a covered patio or a bright room with the windows open on a warm afternoon makes a big difference. Make sure the mattress is fully dry before you remake the bed. Trapped moisture is what turns a small smell into mildew.
How to handle specific smells
Sweat smell
Sweat odor builds up slowly across the whole sleeping area, so treat the surface rather than one spot. Vacuum, mist lightly with an enzyme cleaner or the vinegar solution, blot, then give it a long baking soda treatment. Going forward, a breathable, washable protector and a cooler sleep setup reduce how much sweat reaches the mattress.
Vomit smell
Remove solids first, blot up as much liquid as possible, then apply enzyme cleaner and let it work. Vomit is acidic and protein-heavy, so a second enzyme treatment after the first one dries is often needed. Finish with baking soda and a long air-out.
Pet or human urine smell
Urine is the most stubborn mattress odor because it soaks deep into the comfort layers. Act quickly, blot rather than scrub and use an enzyme cleaner. For cat urine, which is especially strong, expect to repeat the process. Our step-by-step guide on how to clean pee out of a mattress covers this in detail.
Musty or mildew smell
A musty smell means moisture has been trapped in the mattress, often from sitting on the floor, a solid base with no airflow, or a humid room. Dry the mattress thoroughly in the sun, then treat the area with the vinegar solution and baking soda. Improve airflow under the bed with a slatted base or a breathable foundation. If you see visible mold growth, especially deep in the mattress, replacement is the safer choice.
Smoke smell
Smoke clings to fabric and foam. Several rounds of baking soda, vacuuming and airing out in sunlight usually help. Persistent smoke odor in older foam mattresses may never fully clear.
What not to do
- Do not soak the mattress. Foam and fiber layers hold water for days and can grow mildew.
- Do not use bleach. It can damage fabrics and foams and leaves its own smell.
- Do not mask the smell with fragrance sprays alone. The odor returns once the fragrance fades.
- Do not steam-clean memory foam unless the manufacturer says it is safe; heat and moisture can damage it.
How to keep a mattress smelling fresh
- Use a waterproof, breathable protector and wash it every few weeks. Read why a mattress protector is worth it.
- Wash sheets weekly, more often in hot weather.
- Let the mattress breathe for an hour or so after you get up before making the bed.
- Vacuum the mattress and sprinkle baking soda every season or two.
- Keep the mattress on a base that allows airflow.
When it is time to replace the mattress
If an odor keeps returning after several thorough cleanings, the source is likely deep inside the comfort layers where you cannot reach it. Replace the mattress if you see mold, if the smell comes back within days of cleaning, or if the mattress is also sagging or uncomfortable. When you shop, breathable hybrids with coil cores tend to trap less heat and moisture than dense all-foam beds.
Frequently asked questions
How do you get smell out of a mattress?
Strip and wash the bedding, vacuum the mattress, spot-treat any odor sources with an enzyme cleaner, cover the surface with baking soda for several hours or overnight, vacuum again and let the mattress air out, ideally in indirect sunlight. Make sure it is completely dry before remaking the bed.
How do you get sweat smell out of a mattress?
Treat the whole sleeping area rather than one spot. Vacuum, lightly mist with an enzyme cleaner or a mix of equal parts white vinegar and water, blot, then leave baking soda on overnight before vacuuming. A washable protector helps prevent the smell from coming back.
How do you get vomit smell out of a mattress?
Remove solids, blot up liquid, apply an enzyme cleaner and let it sit before blotting again. Repeat once it dries if the smell remains, then finish with baking soda and a long air-out.
How do you get cat pee smell out of a mattress?
Blot up as much as possible, then apply an enzyme cleaner designed for pet urine and let it work for the full recommended time. Cat urine often needs two or three treatments. Dry the area completely and finish with baking soda.
Ready for a fresh start?
If your mattress is past saving, we can help you find a replacement that sleeps cooler and stays fresher. Browse our breathable hybrid mattresses, or take our sleep quiz for a personalized match. We offer same-day delivery across Los Angeles, and every mattress comes with a free 120-night comfort guarantee.
