Several years ago I did a complete restoration on my 8N. At that time the interior of the gas tank was sealed. I do not remember the exact product that I used. I do know that it is gray. Well whatever, the sealant has dissolved and clogged the fuel shut off valve. This tractor is more of a trailer queen and hardly ever leaves the garage. I really do not want to replace the tank for fear of scratching the paint. What are my other options??