This worked for me, I have a `72 XS650, the tank was not too bad but there was rust. I went to walmart, got a small bag of fish tank gravel, smallest diameter and very course, I removed the petcocks and duct taped the holes, dumped the whole bag into the tank then taped the filler hole. I wraped the tank in bubble wrap and taped it very well, I took the tank, put it in the dryer, packed pillows all around it so it couldn`t move, then set the dry on tumble/NO HEAT!!!!! I ran it for an hour, changed position, ran it for another hour. I then pulled it out unwraped it all, dumped all the gravel out, blew out the dust/rust, rinsed with gas, then coated the inside with 10W40!!! When the tank is ready to install, a rinse with gas and it will be ready to go!!!! It looked like a new tank inside!!!!!!