MOMAR  BLOCKBUSTER Dissolves & removes Concrete, Mortar, Cement and Tile Grout from Drains – Acid AlternativeBlockbuster is a safer alternative to sulfuric, hydrochloric (muriatic), phosphoric, and hydrofluoric acids for dissolving concrete, mortar, grout, and cement residues in drain lines. It is also excellent for removing plaster, casting materials, scale, and other minerals from drains, sinks, fixtures, and plumbing.