How to Clean a Sauna: Simple Maintenance That Keeps It Fresh for Years

How to Clean a Sauna: Simple Maintenance That Keeps It Fresh for Years

A well-maintained sauna can last 15-20+ years. A neglected one starts smelling funky within months and develops mold, stains, and structural problems that are expensive to fix.

The good news: sauna maintenance is simple. It takes about 5 minutes after each session and an hour or so per month. Here's exactly what to do and when.

After Every Session: The 5-Minute Routine

This is the single most important maintenance habit. Do this every time and your sauna will stay in great shape with minimal effort.

1. Ventilate

Leave the sauna door open after your last session. If your sauna has a vent, open it. Air circulation is the number one defense against moisture buildup, mold, and that stale smell that develops in closed-up saunas.

Leave the door open for at least 30-60 minutes, or until the sauna has cooled to near room temperature. Some people leave the door cracked overnight. Either works.

For outdoor saunas, make sure the vent is open but the door is secure against weather and animals. A small gap works.

2. Wipe Down the Benches

Use a damp cloth to wipe sweat residue off the benches while the wood is still warm (not hot). Warm wood is slightly more porous and releases surface residue more easily. A quick wipe-down prevents sweat salts from building up in the wood grain over time.

Use plain water. No soap, no disinfectant - just a damp cloth. The heat from the session has already killed most bacteria. You're just removing the moisture and salt residue left behind.

3. Check the Floor

Wipe up any standing water on the floor. If you have a floor drain, make sure it's clear. Water sitting on a wood floor between sessions is how rot starts.

Weekly: Light Cleaning

Once a week, spend 15-20 minutes on a slightly deeper clean.

Bench Scrub

Mix a solution of warm water with a small amount of mild, fragrance-free soap (like unscented castile soap). Use a soft bristle brush to scrub the benches, working with the wood grain. Rinse with clean water and wipe dry.

This removes body oils and sweat buildup that daily wiping doesn't fully address. Body oils are the main cause of darkened, discolored wood on sauna benches.

Floor Mopping

Mop the floor with the same mild soap solution. Pay extra attention to areas around the drain and under the benches where moisture collects. Rinse and dry.

Heater Check

Quickly inspect your sauna heater. Make sure the stones are properly stacked and none have crumbled or shifted significantly. Remove any debris that's fallen between the stones.

Monthly: Deep Cleaning

Once a month, do a thorough cleaning that addresses everything the daily and weekly routines don't cover.

Bench Sanding

This is what keeps your benches looking and feeling like new. Over time, sweat, body oils, and use create a slightly rough or discolored surface layer on the wood.

Use fine-grit sandpaper (120-150 grit) and lightly sand the bench surfaces. Always sand with the wood grain, never against it. You're removing just the top layer of discoloration - a few passes per area is enough.

After sanding, vacuum or sweep up the dust and wipe the benches with a damp cloth. The result is fresh, light-colored wood that looks like it was just installed.

If your sauna gets heavy use (daily by multiple people), you may want to sand every 2-3 weeks. Light use (a few times per week by one person) can go 4-6 weeks between sanding.

Wall and Ceiling Check

Inspect walls and ceiling for any signs of mold, mildew, or moisture damage. Focus on corners, the area behind the heater, and the ceiling directly above the heater where steam rises.

If you find any mold spots (rare in a well-ventilated sauna), sand the affected area down to clean wood. If it's a small spot, fine-grit sandpaper handles it. For larger areas, consult a professional.

Hardware and Fittings

Check door hinges, vent mechanisms, bench supports, and any metal hardware. Tighten anything that's loosened. Look for signs of rust on metal components - the heat and moisture cycle can corrode cheaper hardware over time.

Stone Inspection

Remove the sauna stones from the heater and inspect them. Look for cracking, crumbling, or significant size reduction. Stones that have deteriorated should be replaced - broken stones can block airflow through the heater and reduce efficiency.

Rinse the stones with water to remove dust and mineral buildup, then restack them on the heater. Place larger stones on the bottom, smaller ones on top, with gaps between them for air circulation.

Seasonal Deep Clean (Every 3-6 Months)

A couple times per year, go all-in:

• Full bench sanding - More thorough than the monthly touch-up. Sand all bench surfaces, backrests, and armrests.
• Complete stone replacement assessment - Sauna stones typically last 3-5 years with regular use. If stones are noticeably smaller, heavily cracked, or crumbling, replace the full set.
• Door seal check - Inspect the door gasket or seal for wear. A poor seal lets heat escape and makes the heater work harder.
• Exterior inspection (outdoor saunas) - Check the roof, exterior walls, foundation, and drainage around the structure. Address any issues before they become expensive problems.

What Products to Avoid

This is as important as knowing what to use. The wrong cleaning products can damage your sauna, create toxic fumes at high temperatures, or ruin the natural wood scent.

Never use:

• Bleach - Damages wood fibers, creates toxic fumes when heated, and leaves a chemical smell that lingers for weeks
• Harsh chemical cleaners - Any spray cleaner, degreaser, or disinfectant with strong chemicals is a bad idea. At 180°F, those chemicals off-gas into the air you're breathing
• Varnish, lacquer, or sealant - Never seal sauna wood. The wood needs to breathe and absorb/release moisture. Sealed wood traps heat against your skin and can cause burns. It also peels and blisters in the heat.
• Pressure washers - The force damages the soft wood fibers and can force water deep into the wood, promoting rot
• Scented cleaners - Fragrance chemicals are designed for room temperature. In a hot sauna, they break down and release compounds you don't want to inhale
• Essential oils on wood - If you want aromatherapy, add a drop of eucalyptus or birch oil to the water you throw on the stones. Don't rub oils into the wood - it stains and goes rancid

Safe Cleaning Products

Keep it simple:

• Plain water - Handles 90% of cleaning needs
• Mild unscented soap - Castile soap or similar, diluted in warm water
• White vinegar solution - 1 part vinegar to 4 parts water for stubborn mineral deposits or light mildew. Rinse thoroughly after
• Baking soda paste - For tough stains, make a paste with baking soda and water, apply to the stain, let sit 15 minutes, scrub gently, rinse
• Fine-grit sandpaper (120-150 grit) - For wood maintenance and stain removal

The Bottom Line

Sauna cleaning isn't complicated. The daily 5-minute ventilation and wipe-down does 80% of the work. Weekly scrubs and monthly sanding keep the wood fresh. Avoid harsh chemicals, let the sauna breathe, and inspect components regularly.

Treat your sauna well and it'll serve you for decades. Neglect it and you'll be dealing with mold, odors, and premature wood decay within a year. The maintenance is minimal - build it into your routine and forget about it.