How to Clean a Sauna: Proven, Easy Steps for 2026

By James Kowalski · September 4, 2025

Why Your Sauna Needs a Strict Cleaning Routine

I'll be honest, skipping your sauna wipe-down is incredibly tempting after a long, exhausting sweat session. But I've seen exactly what happens when you ignore it. Sweat soaks deep into the untreated cedar or hemlock wood. Bacteria multiply fast in that warm, humid environment. If you have friends over who skip the towel barrier, you're basically marinating in their skin oils and dead cells.

In my experience maintaining home spas for 8 years, a neglected sauna starts smelling like a damp gym locker within three weeks. You don't want that. Keeping it pristine takes about 15 minutes after each use, and maybe 45 minutes for a monthly deep clean. It's a small price to pay for a hygienic retreat.

My Go-To Supplies for Cleaning a Sauna

Don't grab your standard bathroom bleach. Harsh chemicals ruin the porous wood and release toxic fumes when heated to 190°F. I stick to a very specific, minimalist kit that I keep right outside the sauna door.

White Vinegar and Water: A 50/50 mix in a 32oz spray bottle.
Microfiber Cloths: I use the 16x16 inch Kirkland Signature ones from Costco. They don't leave lint behind.
Fine Sandpaper: 120-grit to 150-grit for stubborn sweat stains on benches.
Glass Cleaner: I prefer Method Glass + Surface ($5-7 a bottle) because it's plant-based and streak-free.
Soft Bristle Brush: A $12 OXO Good Grips dustpan brush works perfectly for the heater rocks.

Let's look at a quick cost breakdown for your starter kit.

Item	Estimated Cost	Replacement Frequency
White Vinegar (1 Gallon)	$4-6	Every 6 months
Microfiber Cloths (12-pack)	$15-20	Annually
120-Grit Sandpaper (5 sheets)	$8-10	As needed
Method Glass Cleaner	$5-7	Every 3 months

Step-by-Step: How to Clean a Sauna Interior

Cleaning the Wood Benches and Walls

Wait until the room cools down to at least 80°F. Spraying cold water on 180°F wood causes cracking and warping. I lightly mist my 50/50 vinegar solution onto a microfiber cloth, never directly on the wood. Wipe down the benches following the wood grain. Pay extra attention to the backrests. That's where the most skin contact happens.

If you notice dark, stubborn sweat stains, let the vinegar sit for exactly 3 minutes. Then scrub gently. For deep, set-in stains that won't budge, I lightly sand the area with 120-grit sandpaper. It removes the top layer of stained wood instantly. Just wipe away the dust afterward with a dry cloth.

Tackling the Glass Door and Hardware

Glass doors get incredibly foggy and smeared with handprints. I spray my Method glass cleaner directly onto a dry cloth. Wiping the glass in a circular motion prevents streaks. Don't forget the wooden handle! People grab it with sweaty hands constantly. Wipe the handle with your vinegar cloth.

For the metal hinges and latch, a quick wipe with a damp cloth prevents rust. I've found that applying a tiny drop of 3-in-One oil ($6 at Home Depot) to the hinges every six months keeps them squeak-free. This isn't the most glamorous task, but it saves you from a screeching door.

Maintaining the Heater and Rocks

Turn off the heater. Let it cool completely. This is non-negotiable. I take my OXO brush and gently sweep dust and debris off the rocks. Over time, the rocks break down and crumble. If you see excessive crumbling, it's time to replace them.

I buy Harvia sauna stones ($30-40 for a 40lb box). Rinse the new rocks outside with a hose before stacking them. This washes off the stone dust that would otherwise burn and smell terrible during your first session. Stack them loosely so air can circulate around the heating elements.

Dealing with Mold and Mildew

Finding black spots in the corners of your sauna is a nightmare. I've dealt with this in client homes where the exhaust vent was blocked. Mold thrives when moisture gets trapped. First, identify the source. Check your lower intake vent and upper exhaust vent to ensure they aren't clogged with dust.

Next, treat the affected wood. I use undiluted white vinegar in a spray bottle. Saturate the moldy area and let it sit for 15 minutes. Scrub it with a stiff-bristled nylon brush. Never use a wire brush on cedar or hemlock. It leaves metal shards that rust and stain the wood permanently. If the mold has penetrated deep into the grain, you'll need to sand it down to bare wood. This isn't the easiest fix, but it saves you from replacing the entire board.

Ventilation and Air Quality

Proper airflow is just as critical as scrubbing the benches. I always tell my clients that a sauna needs to breathe. If your room smells musty even after cleaning, your ventilation is failing. Most traditional saunas use a passive venting system. You need an intake vent near the floor, directly under the heater. The exhaust vent should be on the opposite wall, near the ceiling.

I check these vents every three months. I use a Shop-Vac with a crevice tool to suck out dust bunnies and dead bugs. If you have a mechanical exhaust fan, wipe the blades with a damp cloth. A blocked fan motor will overheat and burn out. Replacing a mechanical vent fan costs around $80-120, plus the headache of wiring it.

Cleaning the Exterior and Control Panel

People forget the outside of the sauna. The control panel gets touched with sweaty hands constantly. I wipe the digital display and dials with a barely damp microfiber cloth. Never spray cleaner directly on the electronics. I've shorted out a $150 control board doing exactly that.

For the exterior wood panels, a simple dusting is usually enough. If your sauna is in a bathroom, wipe the outside down with a mild all-purpose cleaner to remove bathroom humidity residue. When your landlord inspects next week, or when you're just trying to keep your home pristine, the exterior matters just as much as the interior.

Deep Cleaning vs. Daily Maintenance

I break my routine into two categories. Daily maintenance keeps the daily grime away. Deep cleaning resets the room. After hosting a weekend dinner party where six people used the sauna, I always do a full wipe-down immediately. You'll thank yourself later.

Task	Daily (After Use)	Monthly Deep Clean
Wipe Benches	Yes (Damp cloth)	Yes (Vinegar solution)
Clean Glass	No	Yes (Glass cleaner)
Sand Stains	No	As needed
Brush Heater Rocks	No	Yes
Check Vents	No	Yes (Vacuum)

Common Sauna Cleaning Mistakes I See

I've inspected dozens of residential saunas. People make the same errors repeatedly. Avoid these to extend the life of your investment.

Using Bleach or Ammonia: Never do this. The fumes are dangerous when the room heats up.
Leaving Wet Towels Inside: This traps moisture. It guarantees mold growth on the floorboards.
Pressure Washing the Wood: I saw a guy try this. He completely splintered his cedar benches and ruined the heater wiring. Just don't.
Sealing the Wood: Sauna wood needs to breathe. If you apply polyurethane, it traps sweat and gets incredibly slippery and hot.

Choosing the Right Wood for Future Replacements

If you sand a board too many times, it gets too thin. I've had to replace bench slats in my own sauna. Western Red Cedar is my top choice. It costs about $4-6 per linear foot. It resists rot naturally. Hemlock is cheaper at $2-3 per foot, but it stains much faster.

Nordic Spruce is another option, though it tends to splinter if you drop heavy items on it. Always buy kiln-dried wood. Green wood will warp and crack when exposed to 190°F heat. Keep a few extra slats in your garage just in case.

Frequently Asked Questions

How often should I clean my home sauna?

I recommend a quick wipe-down of the benches and floor after every single use. For a thorough deep clean involving sanding and glass polishing, aim for once a month. If multiple people use it daily, bump that deep clean to every two weeks.

Can I use essential oils to make my sauna smell better?

You can add a few drops of eucalyptus or lavender oil to your water bucket, but never apply them directly to the wood or heater. Direct application causes the oils to bake into the wood and creates a massive fire hazard. Stick to water-soluble sauna aromas like the Tylo brand ($15-20).

Why does my sauna wood have dark spots?

Those dark spots are usually sweat stains or early signs of mold from trapped moisture. I tackle sweat stains with a light sanding using 120-grit paper. If it's mold, scrub the area with undiluted white vinegar and ensure your ventilation is working properly.

Do I need to treat the wood with oil?

I actually advise against oiling the benches or backrests because it makes them slippery and hot against bare skin. However, I do rub a light coat of paraffin oil on the wooden door handle once a year to keep it from drying out and cracking.

How do I clean the sauna floor?

Most home saunas have removable wooden duckboards over a tiled or sealed floor. I pull the duckboards out once a month and scrub the floor with a mild dish soap and warm water. Let the floor dry completely before putting the wood back.