When the water evaporates, it leaves the powdery substance. Clean with acetone and a clean white rag.
If stain still remains poultice with a toluene or equivalent solvent and poultice powder. If the etch is very deep, re-honing may be necessary. Is marble or granite best? Cover the paste with a plastic sandwich bag or food wrap.
Problem Pencil can be tricky to remove since the graphic may penetrate into the stone. Please use extra caution when handling all chemicals listed above. Also vomit can leave a stain depending on what was eaten.
Some typical paper poultices are: This can be difficult to remove if left on too long. If stain is deep poultice with a solvent toluene and poultice powder.
The oils and solvents contained in these paints will carry the dyes deep into the stone. When purchasing poultice materials, ask if they contain stain removing chemicals or if they need chemicals added.
Try to remove as soon as grease is spilled. Covering with a wet paper towel will help keep enzyme solution wet. Clean the stained area with water and stone soap.
Commercially available "smoke removers" may save time and effort. Do not use detergent and water-this may set stain. Type All except chocolate, see chocolate. Do not attempt to seal the back of the tile with a silicone sealer. Whatever the reason, one thing is for sure, green marble can warp when set with water based materials.