If you are considering using brick acid, or muriatic acid, to clean your brick, there are some things you should consider. Using muriatic acid is risky because of its potential for damaging material it comes in contact with, including clothing, metal, and skin. The lining of your throat, nose, and lungs can be burned by the acid's toxic fumes. If you decide, despite its potential to cause damage, that this acid is the one you'd like to use to clean your brick, then you should know how to use it safely. Check with the steps you'll find below.
Wear Protective Clothing
When using muriatic acid it is important that you wear protective clothing. Vinyl-coated coveralls will offer some protection from the acid and are available at home improvement stores. You should also purchase and use acid-resistant gloves, eye and face protection, and an effective respirator sufficient to the task. Ask at your home improvement center for their recommendations for these products. To protect your feet, you should consider wearing rubber boots.
Have Neutralizing Agent on Hand
Before beginning your cleaning project, have an acid-neutralizing agent on hand. This could include baking soda or garden lime. Either one of these will neutralize muriatic acid if you should accidentally spill some. Keep water also available in the event the acid comes in contact with your skin.
If you are planning on cleaning brick on the exterior of your home, use a protective covering for your nearby shrubbery. Or, before applying the acid, soak the shrubbery with water.
Ventilate Your Work Area
If you will be working in an area that is not well ventilated, use a fan to exhaust the acid fumes. Never use muriatic acid inside your home.
Mix the Acid
Use a large plastic or glass container only. Never use metal, paper or ceramic containers to mix the acid as they can cause an adverse chemical reation. For cleaning of lighter-colored bricks, use a mixture of 1 part acid to 10 parts water. For darker bricks, use 1 part acid to 20 parts water. When mixing, add the acid to the water, not water to acid. Use extreme caution when mixing, so that the solution does not splash on you. Never mix other chemicals with this acid mixture.
Saturate the Area with Water
Saturate the area you will be cleaning with water from your hose. Use an inexpensive hose, as it will very likely be damaged by the acid.
Apply Acid Solution
Apply the acid solution with a damp brush, and work cautiously, so that the solution does not splatter which is why you need to wear protective clothing. Apply the acid mixture to the highest point of your brick surface first. Then work downward. Clean only a small amount at a time. Before you begin scrubbing, allow the acid solution to set for about six minutes.
Rinse Dark Bricks
If you are cleaning darker bricks, use a garden hose to rinse the acid off the brick. For lighter brick, rinse with a neutralizing solution of bicarbonate soda.