What Is Muriatic Acid? Cleaning Uses and Safety

Muriatic acid effectively removes dried cement products, like mortar, concrete, and grout, from stones, bricks, and other masonry surfaces. Muriatic acid is a powerful and corrosive liquid consisting of hydrochloric acid, water, and other trace minerals.

Besides cleaning masonry, it has other household uses like cleaning rust stains, balancing pH levels in pools, and removing mold. Take safety precautions when using this product; direct contact with the liquid or its fumes can be potentially harmful.

Muriatic Acid Uses in the Home

There are numerous cleaning uses for muriatic acid at home. Muriatic acid comes in different concentrations, so it's best to check the label to ensure the concentration you buy is appropriate for the task. Cautiously use muriatic acid when you need a heavy-duty solution in the home for the following functions:

• To remove stains (including embedded oil stains) and mold from masonry and concrete (even in basements); use a solution of 1 cup of muriatic acid to 1 gallon of water
• To remove stains and mold from tiled or concrete swimming pool surfaces
• To remove rust from stainless steel
• To clean and prep masonry for painting by removing efflorescence (a white crystalline coating)
  
• To clean extremely stained shower and floor tile and grout (though this is best left to professional tile and grout cleaners)
• To clear extremely clogged shower drains (this is also best left to professional plumbers)

Safety Considerations

While this is a very capable cleaning agent, it is also a hazardous product and extreme caution must be used when cleaning with muriatic acid. If the proper safety precautions are not followed, severe injury can result.

However, with the proper precautions, muriatic acid can be used as a highly successful cleaner. Many masons use it at the end of almost every job that involves a stone wall, ​patio, landscape steps, or any other hardscape made with mortar or concrete.

To use muriatic acid safely, wear safety goggles, a mask, rubber gloves, and a protective apron (for splashback).

How to Dispose of Muriatic Acid

If you have leftover muriatic acid, never pour it down a drain for disposal. It is caustic and toxic. It can ruin your drain pipes and hurt the environment.

Your best option is to use what remains. Use a diluted solution to clean sidewalks, add to pools to balance the pH, or cut it (10 parts water to 1 part muriatic acid) to clean toilet bowls. If you can't use it, give it to a hazardous waste disposal facility for proper disposal.

If only a small amount is left (1 cup), neutralize the acidic component by adding 1/2 cup of baking soda and 1 quart of water and disposing it through the sewer drain. However, this may be prohibited by your city or town's local ordinances, so check to remain in compliance.

Tips for Using Muriatic Acid Safely

1. Keep it away from children.
2. Always wear proper safety gear: Thick rubber gloves, a respirator, safety glasses, a long-sleeve shirt, and pants that completely cover your legs. This cleaner can stain your clothes; wear something that you do not mind getting ruined.
3. Be very careful with splashes and spills on surrounding surfaces. The acid can cause permanent damage to wood, plastic, and other surfaces.
4. Have a supply of clean water on hand: This cleaner is almost always diluted with water before being used for cleaning. Water is used to wet the surface before and after cleaning. Always have a running garden hose nearby.
5. When cleaning masonry surfaces, you'll need a plastic bucket. You must always add water to the bucket first. Slowly pour the muriatic acid into the water. Never pour water into acid. It will start a chemical reaction that causes the acid to heat up, aggressively bubbling out of the bucket and splattering onto you. Do not get close to the bucket when pouring the acid; the fumes are intense and can be painful if inhaled.
6. Take time and work slowly. Being rushed leads to muriatic acid spills or splashes.

DIY Projects Using Muriatic Acid

Jobs that could use muriatic acid include laying a tile patio or building a concrete patio. Muriatic acid can also make mirrors look antique by acid-etching them. It is also used to prepare brick or masonry surfaces that will be painted over.