One of the steps required in the process of acid staining is to thoroughly clean the concrete floor before applying the acid stain. Muriatic acid is sometimes used to dissolve grease spots on concrete, but this acid can be harmful to the floor it is applied to and to the person applying it. Although you could theoretically use this acid to clean your concrete floor, it is not safe or advisable.
Effects of Muriatic Acid on Concrete Surfaces
Applying this acid to a concrete surface will leave the concrete surface rough and porous. The surface on which you apply acid etching will need to be smooth and non-porous.