[mass A man]

Don, either go ahead with reggiedog's idea, which is a good one,or first take a small "chip" of this black stuff and do a little chemistry test yourself. Put the chip in a small container and then try adding a drop or two of different solvents. Try to see which solvent dissolves the chip, then go "big-time" with that solvent and try to soak and flush your tank and parts with it. I know this may be a reach--- but does anyone else have an idea?