Stains at most cases can be removed by a process known as poultice. A poultice is a liquid cleaner or chemical mixed with a white absorbent material to form a paste about the consistency of peanut butter applied and left to work for 24 to 48 hours. The liquid cleaner or chemical will draw out the stain into the absorbent material. Poultice procedures may have to be repeated to thoroughly remove a stain, but some stains may never be completely removed. If the poultice doesn’t work, honing or grinding the surface down to a fresh layer of stone and then polishing may help to remove the stain.
Some stains can penetrate completely through the stone body that grinding or honing will not able to remove stain complete, in this case should be used both ways for stain removal.