Posted by Peter the blacksmith on October 14, 2000 at 00:18:32:
When I was a kid and the tanks of our mopeds got wrinkles, we emptied out the gas and filled them with peas, then added water and closed the lid. And waited...Usually, the peas expanded and the tank looked more or less the same.. Try that or send it to my smithy if you're located in Europa.
Good luck ! Peter.