what will dissolve silicone in a gas tank

We have a plastic gas tank thats for our 1977 dodge truck previous owners tryed to fix the sending unit and put silicone on the gasket.Well they ethier droped some in the tank or it slowly fell in over the years, we need to get it out cause it keeps pluging up the whole fuel system and that is just a pain cause you have to take the tank out to get to the sending unit. We need to fix this before we put it back in the truck. Please anybody have ideas as to what we can use to get it out of the tank.