Hi. Do you mean silver-like stains? I have a couple. According to my dentist, it's impossible to remove all mercury from the tooth - when a mercury filling is placed, mercury seeps deeper into the tooth. Some dentists, however, claim to remove all mercury, but mine says that there will be a small amount still in the tooth for the rest of the life of the tooth. He says the mercury will also always be in our bodies, but that over time the level will fall from toxic to manageable.