": I've got rust inside my gas tank that just won't quit. 2-3 times a week I end up disconnecting the gas line and draining off some more rust and paint. Does anyone know of something I can put in there to seal it? Thanks. <p>I've had the same problem. There's a kit you can purchase, it comes in two or three bottles. The one I got came in two bottles. The first one was a deruster, careful with it because it's acid. The second is a neutralizer and a sealer. The process takes between 1-4 hours depending on how rusty the tank is. It is a plus if you can remove the tank, my tank is removable, but with one thats built in it's a little more tricky because the acid can ruin the paint job. If you don't want the hassel you can always send to the shop."