Ceramic Tile Stain Remover
1 T sodium citrate dissolved in 6 T. glycerin
add water until the consistency of milk, add enough Whiting to form a paste.
Spread a coating on and let it set. Rinse off with water.
Add sufficient water to thin to a milk-like consistency.
Mix in enough whiting to form a paste.
Spread a thick coating on stains and let stand. Rinse with clear water.