For removing cement and paint spots from cladding tile
can be a mild acid wash, rather using tile washing chemical (little expensive) is better option.
For kota stone dont use acid since it will fade out the stone rather u can use water jet machine( used for car wash ) to remove hard stains. For stone wash also you get chemicals from different brands like stonera ,fosroc, vito etc..
While installing stone itself its always recommended to cover it with plastic cover till the final quote paintings are done. Stones like sadahrahalli, sera, white shades will turn out pale yellow if washed with hard acids.
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