Concrete etchers and pH reducers from RadonSeal are safer – non-corrosive to skin, no noxious odors, will not "burn" the concrete. For indoor and outdoor concrete
Etching concrete helps to prepare its surface for paints, coatings, stains, and penetrating sealers. Concrete etchers open up the pores in concrete, increase the roughness
of the surface, and reduce the alkalinity of new concrete.
Concrete etchers also clean concrete surfaces and remove stains, including stains from leaves or clay stains.
You can choose between the organic and gentle EasyEtch Concrete Etcher, which is based on citric acid, and the much stronger PowerEtch Concrete Etcher.