[DARISC]

Just Googled this - maybe helpful?

http://www.google.com/url?sa=t&rct=j&q=cleaning%20rust%20from%20motorcycle%20gas%20tank&source=web&cd=1&ved=0CGgQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DHb7 jyf7A4WE&ei=pAgTULfkDqbKiwKL8ICwCw&usg=AFQjCNF0FUaTidDory22iTTalcRYLey64A