Eff-Erayza is a new technology acid cleaner for removing efflorescence, rust stains, limescale, grout haze, mortar mess and fireplace soot. Eff-Erayza is very powerful and generally more effective and safer to use than traditional industrial acids but does not produce noxious fumes, non-corrosive to metals (except for uncoated aluminium) and temporary contact does not burn skin.