Luigi’s Answer:
Cementitious black grout is very difficult to clean up because it is so heavily pigmented. It can stain porous tiles or even glazed ceramic tiles by sitting in the microscopic pores.
Despite disclaimers, tilers will often proceed using dark grout on white wall tiles and providing they are extra vigilant and carefully clean as they go, can have a problem free instalation. Every brand of grout and batch of tiles will react differently so always test prior to installation.
The safest solution and the recomendation of The Tile Depot is the use of Aquamix Grout Release prior to grouting.
For problem shooting, a poultice may be able to draw out the pigment or the use of diluted vinegar has been proven to work on occasion. We suggest Aquamix Poultice Stain Remover.
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