To remove grout from a tile patch area, use a scouring pad on a sponge to gently go ontop of the tiles to remove grout and see where you need to rub harder, but dont rub hard on the actual joint. Don't get your sponge too wet. Once you have everything off the tiles, work on the grout. Make sure you get the grout lines to make them look neat and clean. Make sure the seams are tight and flush, run your sponge over it to clean it up a bit. If you have a missing tile filled with grout, use a wet sponge to flatten down any edges and make it look neat. It will take off excess grout and help conture the grout. AFter you have made the tile patch look neat and clean, allow it to dry.