I used Diedrich 101 Masonry Restorer to clean some old dirty granite, now I have yellow stains appearing, why?
Granite normally has high iron content. The yellow staining is the iron in the stone starting to oxidize. The product that should be used to clean granite is the Diedrich 101G Granite and Terra Cotta Cleaner. It is specially formulated incorporating a rust inhibitor to address those instances where iron may present in the surface to be cleaned. A couple of other instances where the 101G might be better suited for cleaning are white face brick and some sandstone that may exhibit the presence of iron in the stone by yellow, orange or reddish stains.
