If you can remove the piece it's on I've found the best way to remove it is with fingers then rinse what it was on before returning to the tank, but if they are really small bubbles a toothbrush works fantastically. I trim the sides of the brush until there's about a half centimeter mohawk down the middle. I find it great for removing any nuisance algae or detritus in between frag polyps. As long as you're delicate it won't bother soft polyps IME