The best way to remove silicone sealant is to soften it with long-term exposure to mineral spirits to attack its bond and then scrub the remaining residue with a brush, although a razor knife might be necessary for the most stubborn areas. No solvents dissolve silicone sealant, so there are no shortcuts.
It might be tempting to get sandpaper out to scrape away the residue. However, even with the coarsest grit, silicone sealant just makes the sandpaper gummy, taking away its abrasive properties. If you are dealing with a finished surface, try denatured alcohol instead of mineral spirits to preserve the finish. Test any surface with the mineral spirits in an unobtrusive spot to see if any discoloration takes place.
A utility knife or razor is glided across the surface with the silicone sealant. By holding the blade carefully and sliding using upward and downward movements, the silicone sealant peels off from the surface. One can switch to the opposite side of the silicone sealant and repeat the exercise. The sharp blade peels off the unwanted materials by putting it at an angle to avoid gouging the tiled surface. Any small strands of the silicone sealant can be rubbed using one's fingers.
A damp scouring pad dipped in acetone is an effective solution to wash off remaining silicone sealants after peeling. It is swiped over the tile carefully, while scrubbing where necessary. This helps to avoid soaking the surface, which could cause damage. Application of mineral spirits on the gouged surface also removes any excess silicone sealant by dissolving it. Wiping the surface with warm water is effective in removing any stains and smell left after application of acetone and alcohol on the surface.