Here's a question posted by daiz in our most recent open thread :
Any ideas on the best way to get grout off tile after grout is applied?! Grouting is hard, hard work, but the tile oh so pretty!
Removing excess grout material from tile is nearly impossible if one of two factors come into play: if the grout has set for over 2 weeks and/or the grout is composed of an epoxy grout. We're going to defer to this excellent and informative piece by the folks over at Ask the Builder about removing excess grout:
The grout removal process requires just a few simple tools. You need some small pieces of wood that have very square-cut edges and several brand new nylon scouring pads. The first thing to do is to work in a small area to see how successful the grout removal techniques will be. If you have rapid success and can get a few tiles clean within a few minutes, that is a very good sign.
Use the wood sticks to remove large clumps and layers of grout. Do NOT use metal scraping tools, putty knives, etc. The metal will permanently damage the glazed surface of the tile. I prefer to use pieces of oak that are 1/4 to 3/8 of an inch thick, one-inch wide and perhaps six inches long. The oak hardwood holds its square cut edge longer than a softwood. Use a power saw to make sure all of the edges are square cut instead of slightly rounded. The crisp square edge aggressively cuts through the grout down to the surface of the ceramic tile.
Read the full instructions from Ask the Builder here.
[Image from How To Grout Ceramic Tile ]