How to Clean a Cast Iron Tub

Cast iron bathtubs are long-lasting and stylish fixtures that become the focal point of your bathroom. They are popular because they retain heat significantly better than fiberglass or steel bathtubs. However, cast iron is coated with a layer of porcelain enamel fused to the cast iron in a furnace. The cast-iron surface is highly durable but is susceptible to chips and scratches.

Because of the delicate nature of the finish, abrasive cleaners can damage it. You must choose a cleaner wisely to ensure you do not scratch the coating of the tub. The best cleaner for cast iron tub surfaces is a mild dishwashing detergent.

What Makes Cast Iron Bathtubs Get So Dirty?

Your bathtub is one of the most frequently used fixtures in your home, collecting skin, bacteria, and soap scum after every use. As the enamel surface wears down, it accumulates grime, dirt, and hard-water deposits.

Rinsing with warm water is not enough to remove these particles. More aggressive cleaning products are required to eliminate the dirt and grime that linger in your tub.

The “Don'ts” on How to Clean a Cast Iron Tub

Before you can understand how to clean cast iron bathtub fixtures, knowing what not to use is essential. Some cleaning products will tarnish the surface, potentially causing permanent damage. Steel wool and scouring powders should not be used at all because they are too harsh and can ruin the finish.

It’s best to avoid acidic products on the surface of a cast iron bathtub as well. Liquids like vinegar and other cleaning agents contribute to the wearing away of enamel. The lining eventually becomes unpleasant to touch and causes the tub to become discolored.

Preparing the Bathtub for Cleaning

Before starting the cleaning process, you’ll want to prepare the tub to make it easier to clean more thoroughly and effectively. This step requires additional effort, but it will ultimately enhance your ability to get to hard-to-reach areas.

Remove the Hardware

Some fixtures on your cast iron tub may be removable, like an overflow drain cover. Carefully remove these components to create more accessibility to the nooks and crannies of the tub where soap scum, dirt, and grime accumulate.

Removing these pieces of hardware has several advantages, especially when you’re learning how to clean a cast iron tub. With the hardware out of the way, you have better access to tight spaces around the drain. You’ll easily reach these obstructed areas, ensuring a more thorough cleaning.

When the hardware is in place, it becomes susceptible to scratching and other surface damage. Removing it minimizes the risk of causing your tub to have imperfections. As a result, you’ll have a beautiful, sparkling cast iron bathtub.

How to Clean a Cast Iron Tub

After preparing the bathtub, it’s time to get to work. Gather all of the necessary supplies before squeezing out the first drop of soap. You’ll need:

Non-abrasive soap or tub cleaner
Soft sponge
Soft cloth or towel

These are common household items that you likely already have. If not, they are inexpensive and easy to find at hardware or other retailers. The following steps are for a deep cleaning that should be completed once every month.

Step 1 - Soak Your Tub

Heating the walls of the bathtub before cleaning will make it a bit easier to remove dirt and grime. Fill the tub with 3-4” of hot water, making sure to splash water on the walls of the tub. As it fills, place a few drops of dish soap into the water. It’s perfectly acceptable for the mixture to bubble up.

Allow it to soak for approximately 30 minutes to give the soap time to break down the dirt and soap scum. Fully drain the water, and the walls of the bathtub will be warm and ready to clean. Use the faucet and hot water to rinse away any remaining soap from the tub’s surface.

Pro tip: Use dish soap with a grease-cutting agent for the best results.

Step 2 - Mix the Cleaning Agent

Mix 1 gallon of hot water with 2 tablespoons of non-abrasive cleaner or dish soap. Place the mixture into a spray bottle and hold it 6”–12” from the cast iron bath surface. If it’s your first time cleaning the tub or using a new product, test a small, inconspicuous space first.

For stubborn stains and rust stains, spray the mixture directly onto the problem area. The product will penetrate the buildup and loosen the soil, making it easier for you to remove.

While the best cleaner for cast iron tubs is a mild soap, other products are effective but have slightly higher risks. Ammonia, for instance, removes soap scum but is a harsh cleaner and requires you to wear gloves.

Pro tip: Never combine ammonia and bleach. When mixed, these chemicals create a toxic gas.

Step 3 - Scrub the Surface

Thoroughly saturate a soft sponge or cloth, like microfiber. Gently scrub the surface of the tub. Never use a coarse sponge or scrub overly forcefully. Too much force or abrasiveness can cause the surface to scratch.

A damp Mr. Clean Magic Eraser is an excellent tool for wiping down the inside of the tub. This sponge safely removes marks and residue around the faucet, drain, and shower head.

Regardless of the type of scrubbers you use, work them in small circular motions to loosen the dirt and soap scum. You may need to spend more time on certain areas to ensure they are fully cleaned.

Pro tip: Don’t forget about the faucet, drains, and shower doors. These areas also collect grime.

Step 4 - Final Rinse

Use the shower head or faucet to rinse the tub thoroughly with hot water, making sure there is no soap or cleaner residue left behind.

Pro tip: If you have a classic clawfoot tub without a shower head, you can fill a bucket with water and use it to rinse the basin.

Step 5 - Dry the Tub

Shut off the faucet and wipe the surface dry using a lint-free cloth. Remove any lingering water, as well, because it can contain cleaning agents that will leave a white film on the tub.

Pro tip: After drying the tub, run your hands throughout the basin to ensure there is no more soap scum. If you find a grimy area, clean, rinse, and dry that portion of the tub again.

FREQUENTLY ASKED QUESTIONS (FAQ)

How Often Should I Clean My Cast Iron Tub to Keep It in Good Condition?

You should rinse and wipe the tub daily to avoid soapy buildup from accumulating. Ensure that the faucet is completely shut off to prevent water from dripping and causing the basin to rust.

Are There Any Special Cleaning Considerations for Antique or Vintage Cast Iron Tubs?

Antique or vintage cast iron tubs often have a clawfoot bottom and require additional steps. As well as cleaning the tub, you must clean the floor. This extra step can be challenging if the bathtub is connected to the wall.

Can You Use Bleach on a Cast Iron Tub?

Do not use bleach to clean your cast iron bathtub. This will cause red streaks to appear along the surface of the tub. Instead, use any non-abrasive cleaner or dish soap.

What is the Best Cleaner for Bathtub Stains?

For weekly cleanings, we recommend using a non-abrasive cleaner, such as this tub cleaner or soap. You can even use your favorite dish soap!

Can I Repaint or Refinish a Cast Iron Tub After Cleaning It?

You can repaint or refinish your cast iron tub after it has been thoroughly cleaned. This is an effective and affordable way to repair chipped porcelain or update it to a modern color.

Removing any impurities before placing the new coat of paint or finish will help it adhere to the surface. You might want to invest in a specialty cleaning product if you have rust spots or hard water deposits.

How Do I Address Chips or Scratches in the Enamel of My Cast Iron Tub During Cleaning?

When cleaning your cast iron tub, you must purchase an enamel repair kit if you find any scratches or chips. Most hardware stores carry these kits, but it’s important that you get the right color.

Start the repair by sanding the affected area with a 600-grit sandpaper. Rinse away the residue and allow it to dry. Then, prepare the enamel kit according to the directions and use a small brush to fill in the holes. You may need to apply more than one layer. Allow the area to dry for 24 hours before using the tub.

How Can I Prevent Rust or Discoloration on My Cast Iron Tub?

One way you can prevent rust and discoloration from forming in your cast iron tub is by investing in a water softener. Rust develops because of iron deposits in the water. Having a quality water softener will eliminate this mineral and several others, like calcium, lime, and magnesium.

Wiping down your tub after every use will also prevent these problems. Rust develops when water droplets and soap scum get left sitting on the surface.

In addition, leaving metal cans in your tub allows small rust circles to form on the surface. Putting these cans into a cabinet or on a shower rack will minimize the formation of rust rings.

Maintaining A Clean Cast Iron Tub

After you take the time to get your tub looking brand-new, you’ll want to keep it that way. You can ensure that you always have a clean bathtub by rinsing and drying the basin with a soft cloth after each use. This post-bath step will prevent you from repeating the deep cleaning more often.

Another way to maintain the beauty of your tub is to avoid abrasive cleaners. Many people use white vinegar as a cleaner. Just remember that it can discolor and damage a porcelain enamel finish on a cast iron tub.

Clogged drains lead to more soap scum buildup, so keeping them clear will prevent stuck-on grime. Consider using a drain catch to collect hair and other loose particles that cause a blockage.

Get Cast Iron Tubs From Vintage Tub & Bath

Cast iron tubs make a beautiful addition to any bathroom. If you want to give your home a vintage look, take the next step and invest in one of these classic tubs. Call Vintage Tub & Bath today to learn more about our options and how we can help.