I would use air pressure and blow through the line into the tank. If that doesn't clear it up you might want to think about cleaning the tank. Anything in the tank now will just get picked up by the fresh gas and end up in your fuel filter, flushing the tank will loosen up all of that so you can get it out. If you go one step futher and have it cleaned by a radiator shop they can flush it and seal it at the same time.
