Muriatic acid is diluted hydrochloric acid and is a very potent chemical.
Cleaning oil from concrete with muriatic acid.
It cleans concrete by removing the topmost layer of your driveway.
Despite its effectiveness muriatic acid should be used on concrete stains only if you ve tried gentler alternatives to no avail.
Use it only as a last resort to clean stains.
The surface becomes etched and clean which allows for the proper adhesion of a new coating.
The acid works well on concrete and on many masonry projects because it neutralizes alkalinity.
Before washing your driveway with muriatic acid try a degreaser on oil stains and a solution of one part bleach to three parts water on mold and mildew.
Make sure the detergent you use is ammonia free.
Scrub the gray stain with a solution of 1 cup liquid chlorine bleach 1 cup powdered laundry detergent and 1 gallon of very hot water.