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To freshen a smelly mattress, strip the bed, vacuum the surface and cover it with baking soda for 1 to 24 hours. Then vacuum it up and let the mattress air out. For stains, spot clean with a light mist of 1:1 white vinegar and water or a mild detergent paste, and never soak the mattress. Once it smells fresh, a washable mattress protector is the easiest way to keep it that way, because it stops sweat, spills and dust from reaching the foam.
Key takeaways
- Most mattress odors come from sweat, body oils, spills, dust and trapped moisture.
- Baking soda is the best all-over deodorizer. Vinegar and mild detergent are best for spot cleaning stains.
- Keep foam lightly damp, never soaked, and let it dry completely before you make the bed.
- Essential oils only mask odors, and concentrated oils can be dangerous for pets.
- A washable mattress protector is the simplest way to stop odors before they start.
Why mattresses start to smell
Foam is porous, so a mattress slowly absorbs whatever is around it and whatever happens on it. The most common causes are:
- Sweat and body oils. Everyone sweats a little at night. Over months, that moisture and oil soaks through the sheets and into the top layers of the mattress.
- Spills and snacks. Coffee, drinks and crumbs in bed leave residue that can turn sour.
- Dust, dust mites and pet dander. These build up in and around the bed, especially without regular cleaning.
- Humidity and trapped moisture. A mattress that can't breathe, or sits in a damp room, can start to smell musty. The U.S. Environmental Protection Agency recommends keeping indoor humidity below 60 percent, ideally between 30 and 50 percent.
Figuring out the cause tells you which method to use. A general stale smell calls for an all-over deodorizer, a stain needs spot cleaning, and a musty smell means the mattress needs to dry out.
6 ways to freshen a mattress, compared
| Method | Best for | Time | What it does |
|---|---|---|---|
| Baking soda | General stale or sweaty smells | 1 to 24 hours | Absorbs moisture and odors across the whole surface |
| White vinegar and water | Stains and stubborn odors | 30 minutes, plus drying time | Breaks down residue and neutralizes odors |
| Mild detergent paste | Visible stains | 30 to 60 minutes | Lifts stains from the surface |
| Cornstarch and baking soda | Sweat and body oil smells | 1 to 24 hours | Absorbs oils as well as moisture |
| Airing out | Musty or damp smells | 3 to 4 hours, repeated | Dries out trapped moisture |
| Essential oils | A light scent after cleaning | A few minutes | Masks odors; doesn't remove them |
Before you start, remove all the bedding and wash it, and check your mattress's care label and warranty. Harsh chemicals and soaking can damage foam and may affect your warranty.
How to use each method
1. Baking soda: the all-over refresh
If there's no visible stain, treat the whole mattress instead of spot cleaning.
- Vacuum the mattressUse the upholstery attachment to remove dust, crumbs and debris, including along the seams.
- Sprinkle baking sodaCover the whole sleep surface with a thin, even layer. A queen or king may take a full 1-pound box.
- Spread it evenlyWork it lightly across the surface with your hand or a soft brush.
- Let it sitLeave it for at least 1 hour and up to 24 hours. The longer it sits, the more it absorbs, and opening a window helps.
- Vacuum it upVacuum slowly and thoroughly until no powder is left.
2. White vinegar: for stains and stubborn odors
Mix equal parts distilled white vinegar and water in a spray bottle. For a stain, mist the area until it's damp but not soaked, wait 30 minutes and blot with a clean, damp cloth. To freshen the whole mattress, vacuum first, then mist the surface lightly. Let it air dry completely before you make the bed. The vinegar smell fades as it dries.
3. Mild detergent paste: for visible stains
Check the care label first for any cleaners or bleach to avoid. Mix a small amount of gentle, bleach-free detergent with baking soda to make a paste about as thick as toothpaste. Spread it on the stain, let it dry for 30 to 60 minutes, then scrape it off with a spoon or dry towel and vacuum the rest.
4. Cornstarch: for sweat and body oils
Cornstarch is good at absorbing oils, which makes it useful for sweat smells. Vacuum the mattress, then spread an even mix of cornstarch and baking soda over the surface. Leave it for 1 to 24 hours, then vacuum it all up.
5. Airing out: for musty or damp smells
On a dry day, strip the bed, open the windows and run a fan to move air around the room. If you can, stand the mattress on its side or prop it up so air reaches the bottom too. Leave it for 3 to 4 hours, and repeat once or twice a week until the musty smell is gone. Check your mattress's care instructions before standing it up, since some mattresses shouldn't be stored on their side for long. If a spill soaks in, dry it fast: the EPA notes that wet materials dried within 24 to 48 hours usually won't grow mold. If you see mold, replace the mattress.
6. Essential oils: a finishing touch
Essential oils don't neutralize odors. They cover them with a pleasant scent, so use them only after cleaning. Add 15 to 20 drops of your favorite oil to a box of baking soda before you sprinkle it on, or add a few drops to the 1:1 vinegar spray, then mist lightly and let it dry.
Be careful with essential oils: some people's skin reacts to them, so test a small amount first. If you have pets, talk to your veterinarian before using them. The ASPCA warns that "in their concentrated form (100%), essential oils can absolutely be a danger for pets."
A simple routine to keep your mattress fresh
It's much easier to prevent odors than to remove them. This routine keeps sweat, dust and moisture from building up:
| How often | What to do |
|---|---|
| Every morning | Pull back the covers for 20 to 30 minutes so moisture can escape before you make the bed |
| Weekly | Wash sheets and pillowcases; hot water helps with dust mites |
| Every 1 to 2 months | Wash your mattress protector |
| Every 3 to 6 months | Vacuum the mattress, deodorize with baking soda, rotate it head to foot and clean the bed frame and the floor under the bed |
| Every few months | Wash comforters and duvets, and clean pillows according to their care labels |
For dust mites, Cedars-Sinai recommends washing sheets, pillowcases and blankets in hot water (130°F) and using zippered, dust-proof covers on mattresses. A breathable foundation or slatted base also lets air flow under the mattress, which helps prevent musty smells.
The best way to prevent odors: a mattress protector
Every cleaning method above treats odors after they've already soaked in. A mattress protector stops them at the surface. It sits under your fitted sheet, blocks sweat, spills and dust from reaching the foam, and goes straight into the washing machine.
There are two main styles. A fitted (5-sided) protector goes on like a fitted sheet and covers the top and sides. A fully encased protector zips around all six sides, which also guards the bottom against dust and is the style recommended for bed bugs and dust mite allergies.
| Protector | Best for | Price |
|---|---|---|
| Single Sided Polyester | Everyday spills and sweat on a budget; guest and kids' beds | From $29 |
| 5-Sided Rayon Bamboo | Soft, moisture-wicking protection for sweaty sleepers | $79 to $119 |
| 5-Sided Super Cooling | Hot sleepers who want to stay dry and cool | From $159 |
| Fully Encased 360° | Full coverage against dust, dust mites and bed bugs | $79 to $119 |
Not sure which one you need? Read our full guide: What Is a Mattress Protector and Do You Need One?
A tip from the MLILY team: put a protector on the day your new mattress arrives. A fresh mattress is the easiest one to keep fresh, and a clean, stain-free mattress also keeps your warranty options open.
Frequently asked questions
How do I make my mattress smell fresh again?
Strip the bed, vacuum the mattress, cover it with baking soda for 1 to 24 hours, then vacuum it up and let the mattress air out. Spot clean any stains with a light mist of 1:1 white vinegar and water.
How long should baking soda sit on a mattress?
At least 1 hour and up to 24 hours. The longer it sits, the more moisture and odor it absorbs.
Can I use vinegar on a memory foam mattress?
Yes, as a light mist of equal parts white vinegar and water. Don't soak the foam, and let it dry completely before you put the sheets back on. Check your care label first.
Why does my mattress smell musty?
Usually trapped moisture from humidity, sweat or a spill. Air it out on dry days, keep indoor humidity between 30 and 50 percent, and use a breathable foundation. Replace the mattress if you see mold.
Do essential oils remove mattress odors?
No. They mask odors with a scent. Clean the mattress first, and be careful using concentrated oils around pets.
How do I keep my mattress from smelling?
Use a washable mattress protector, wash sheets weekly, air out the bed each morning and vacuum and deodorize the mattress every 3 to 6 months.
Keep your mattress fresh from day one
MLILY mattress protectors are machine washable and come in every standard size, from budget-friendly basics to cooling and fully encased styles.
Sources
- U.S. Environmental Protection Agency, A Brief Guide to Mold, Moisture and Your Home.
- Cedars-Sinai, Your Child's Allergies: Dust Mites.
- ASPCA, Latest Home Trend Harmful to Your Pets: What You Need to Know.
- MLILY USA product pages: Single Sided Polyester, 5-Sided Rayon Bamboo, 5-Sided Super Cooling and Fully Encased 360°.
