Want to remove a stain without damaging the smooth surface of furniture and countertops? Use toothpaste. The extra mild abrasives in toothpaste remove stains without scratching the surface. I have used toothpaste to remove water stains on finished furniture and stains on kitchen countertops. It also works on small rust stains. Simply rub a dab into the stain for about 30 seconds and wipe it away.