Gas Tank Reconditioning

I wouldn't recommend it. Unless you are the original owner and meticulously maintained it, an old tank is gonna have rust in it that is diffucult to remove and prevent from returning. There's cleaning and sealant kits you can buy for the inside and most radiator shops will boil it out for you. But the results are not always good. You can get a new one for not much more after you're done with all that time, money and effort. Paint it, install it, keep it full and never worry about it again.