To keep the new gas tank in my Power Wagon from rusting inside, I'm going to give POR-15 Fuel Tank Sealer a try. I've never used it before and it's not sponsoring the video, but I've heard good things about their products. I won't know how well it works for some time, though, since there's a lot left to do on this truck before it gets gas.
POR-15 Fuel Tank Sealer: https://amzn.to/4eZOD5N