Unfortunately cleaning is not a one-size-fits-all process for pavers. For example, masons will use muriatic acid on clay brick to remove mortar. However, muriatic acid could do serious damage to a concrete paver.
Light coloured bricks – 1 part hydrochloric acid to 20 parts water o Dark coloured bricks – 1 part hydrochloric acid to 10 parts water o Under no circumstances should more than 1 part hydrochloric acid to 10 parts water be used. It is better to scrub more vigorously than to use more acid.
Acids and acid-based cleaners can, and all-too-often do, cause devastating damage to the appearance of some types of paving. However, being wise after-the-fact is all too easy.
SOAK WITH BAKING SODA
Since it's a natural cleaning agent, baking soda is one of the safest materials you can use to remove oil stains. Pour baking soda on the stained spot, then add a bit of warm water. You can add some detergent or white vinegar for a stronger vinegar solution.
Additional Muriatic Acid Tips
This acid wash can do severe damage to your concrete pavers. If the concentration is too high, the acid will start to eat away at the surface of the pavers. Closely follow the directions on the container to dilute the muriatic acid. Most products recommend a 12:1 ratio of water to acid.
Unfortunately cleaning is not a one-size-fits-all process for pavers. For example, masons will use muriatic acid on clay brick to remove mortar. However, muriatic acid could do serious damage to a concrete paver.
Dilute white vinegar with water in a bucket, at Walmart (a 50:50 solution is fine), and apply this natural, eco-friendly cleaning solution to the paving slabs with a firm brush and rinse thoroughly.
Acidic cleaners: Harsh, acid-based cleaning products and stain removers can damage the seal and finish of your concrete pavers. Bleach: This alkaline solution may be effective for other household uses, but it can discolor concrete pavers that have been colored or stained.
3) Apply the acid solution with a masonry cleaning brush, soft brush or a low-pressure (less than 40psi) sprayer. 4) Allow the solution to remain on wall for 3 - 6 minutes before scrubbing. 5) Never allow the acid solution to dry out on the brickwork as it can result in white staining.
If you just put the acid on dry brick, there is a chance you can burn or damage the brick. Always work in the shade, not the direct sun. Never allow the acid solution to touch glass, window trim, painted surfaces, aluminum windows, etc. Only apply the acid solution to the brick.
Bleach (For Mold, Mildew, and Moss): A bleach mixture is ideal for removing mold, mildew, and moss from exterior brick walls. Combine a tablespoon of bleach with a gallon of warm water in a bucket, then apply the bleach with a sponge to the brick.
Cleaning concrete with muriatic acid can be a highly effective solution if used correctly, providing ultra-bright white concrete and removal of many types of stains. In one application, you can remove rust stains, oil stains, algae, and paint splatter with a quick chemical application followed by pressure washing.
Warm water and a masonry sponge can remove a lot of grime. Adding dish soap or vinegar also work well. Less is more when cleaning brick.
To clean paver slabs, you can use a detergent, such as Dawn, or a vinegar-water solution that is gentle enough to effectively clean without causing damage to your concrete pavers.
First, for very mild cases of efflorescence, try a 50/50 mix of white vinegar and water. Using a scrub brush, spot treat and scrub affected areas with the vinegar mix. The acidity in the vinegar helps remove the efflorescence and calcium deposits by breaking down mineral crystals.
The acid content in vinegar is particularly good at breaking down the molecules in clay surfaces. Standard bricks are made mostly from clay, so exposure to undiluted vinegar will quickly result in discolouration and a sticky chemical byproduct coating your bricks.
It is common to mix bleach with water; however, you can also add other ingredients to make it more effective. Similar to cleaning pavers with muriatic acid, avoid an intense concentration of bleach, as it can damage the pavers.
Pressure washing is one of the most effective ways to clean your pavers. However, if not done properly it cause permanent damage and deterioration to the surface. Excessive water pressure may remove dirt and grime build-up but it can also eat away at the material.
Mild detergent and water.
Mix some mild dish soap with water in a bucket to create suds, then use a brush or a sponge to scrub the surface of the pavers. If your pavers are textured or have intricate designs, this cleaning method can be gentler than a power washer.
Apply the Solution: Spray the diluted muriatic acid solution onto the pavers, making sure to cover all stained areas. Allow the solution to sit for 15-20 minutes, or as instructed by the manufacturer. Scrub the Pavers: Using the scrub brush, gently scrub the pavers to remove the stains.
If vinegar does not do the trick, you can also try mixing about a cup of bleach for each gallon of water and using this as your mold-killing spray solution.
Never add water to acid, as an exothermic reaction will occur, propelling the acid out of the container and onto you. Never pour muriatic acid into an empty vessel. Fill the container with the right amount of water before adding the acid. Never mix muriatic acid with other acids.