The Easiest Ways to Remove Soap Scum From Your Bathtub (Without Scratching It)

No matter the material or price tag, no bathtub is immune to dirt, especially soap scum. "In short, soap scum is the hardened fats from soap bars ... binding to the calcium and magnesium in the water," explains cleaning expert Ryan Knoll. This reaction creates the chalky residue that you may commonly see in your tub, particularly in areas that stay wet (like the bottom of the soap dish, grout lines, or right around the drain). 

So how do you remove soap scum from your bathtub without scratching or dulling its surface? Read on for the best methods, according to cleaning professionals.

Baking Soda and Vinegar Spray

Suitable for fiberglass and acrylic tubs

For fiberglass or acrylic tubs with light-to-moderate buildup, use Knoll’s method, which uses two common pantry staples.

1. Sprinkle baking soda over the areas with soap scum.
2. Spray with white vinegar until the solution fizzes. Let sit for 15-20 minutes.
3. Scrub gently with a soft, damp sponge.
4. Rinse and dry with a microfiber cloth to prevent water spots. 

Dish Soap and Vinegar Method 

Suitable for plastic and acrylic tubs

“This is the MVP in our playbook,” says Knoll. “Especially for tubs in hard water areas.”

How does it work? “Vinegar is acidic and breaks down mineral deposits, while dish soap dissolves body oils,” explains cleaning expert Petya Holevich. (Just be sure to avoid abrasive scrubbing pads to prevent scratching surfaces.)

1. Mix equal parts dish soap and vinegar in a spray bottle.
2. Spray generously wherever there is soap scum buildup.
3. Let sit for 30-60 minutes (the longer, the better). 
4. Wipe the area down with a non-scratch sponge.
5. Rinse well and wipe down with a microfiber cloth.

Lemon and Baking Soda Paste

Suitable for porcelain or enamel tubs

Most vintage tubs were constructed of iron with a porcelain or enamel coating, which calls for gentle and natural cleaning solutions. With this method, "your tub will smell like lemonade—not vinegar—which is always nice," adds Knoll.

1. Squeeze lemon juice into a bowl. Mix in baking soda until a gritty paste has formed.
2. Rub the paste over the soap scum, using a sponge or the lemon rind itself. Let sit for 15-30 minutes on the heavily soiled areas. 
3. Scrub gently, with a soft sponge or nylon brush.
4. Rinse thoroughly with warm water and dry with a microfiber cloth to prevent streaks.

Hydrogen Peroxide and Baking Soda Method

Suitable for tiles and grout

For grout and any adjacent tiles, Holevich recommends using a hydrogen peroxide and baking soda mix. “Hydrogen peroxide acts as a mild bleach and disinfectant, which is ideal for grout and tile areas that can trap soap scum and mildew,” she says. 

1. Make a paste by mixing the hydrogen peroxide and baking soda.
2. Apply the paste directly onto the grout lines or tiles with visible soap scum.
3. Let sit for 10-15 minutes to loosen buildup.
4. Scrub the areas gently with a soft brush or toothbrush.
5. Rinse thoroughly with warm water.

Baking Soda Paste Method

Suitable for natural stone tubs

To clean natural stone tubs, such as granite, marble, or travertine, anything acidic must be strictly avoided. A mix of baking soda and warm water is enough to preserve the surface while removing any appearance of soap scum.

1. Mix baking soda with water to form a thick paste.
2. Apply to the soap scum areas of your tub.
3. Let sit for 10-15 minutes.
4. Rinse well and let air dry, or use a microfiber cloth for a streak-free appearance.

Polymer Sponges (or "Magic Erasers")

Suitable for most bathtub surfaces

Knoll recommends polymer sponges (commonly known Mr. Clean Magic Erasers) for most bathtub surfaces, as they are mostly non-abrasive. However, you should always test in an inconspicuous corner first before using. “Think of it like super-fine sandpaper,” says Knoll. “Gentle, but still has friction.”

1. Wet the sponge and wring it out.
2. Scrub the soiled areas gently, in circular motions.
3. Rinse well with warm water and dry with a microfiber cloth.

Commercial Soap Scum Removers

Suitable for most bathtub surfaces, with the exception of natural stone

For extreme soap scum buildup, there is always the option of commercially available cleansers, such as CLR, Rejuvenate, or Kaboom. Plenty of air circulation and gloves are recommended for their use, and you should always check that the product is safe for your tub's specific material before using it to avoid damage, says Holevich. Also, avoid mixing cleaners as you could easily create a toxic combination.

1. Spray your cleanser of choice directly onto the soap scum.
2. Let it sit according to the product label instructions (usually 5-10 minutes) to thoroughly dissolve the buildup.
3. Scrub gently with a soft sponge or brush, focusing on stubborn areas.
4. Rinse thoroughly to prevent any strong odors from being left behind. 
5. Dry the cleansed areas with a microfiber cloth.

Tips for Preventing Soap Scum Buildup 

According to Knoll, the longer the soap scum is ignored, the harder the residue becomes, as it traps body oils, dirt and mildew. It is especially prevalent in areas that use hard water. Follow these preventative expert tips to keep your tub gleaming and your cleaning time to a minimum.

• Rinse after every use. Use warm water to rinse the tub walls and floors after each bath or shower, says Holevich. This removes any residual soap, body oils, and minerals before they have a chance to turn into soap scum. Afterwards, dry your tub or shower by using the bathroom fan, opening a window, or wiping it down with a clean towel or squeegee.
• Switch to liquid soap or body wash. “Fats like tallow or coconut oils are what holds the soap bar together,” explains Knoll, but these also are what cause soap scum. Because liquid soaps don’t incorporate fats like this, they are less likely to create buildup.
• Install a water softener or use a filter. Hard water contains calcium and magnesium, which combine with soap to form scum, says Holevich. A water softener or a shower filter reduces these minerals and slows accumulation.
• Engage in regular cleaning. Even a weekly wipe with a mild cleaner or vinegar solution prevents scum from hardening, making deep scrubbing unnecessary,.
• Consider preventative sprays. After cleaning, lightly mist the tub with a vinegar-water solution or a commercial anti-limescale spray. This creates a thin barrier that repels buildup.