Fuel Tanks 1973 F100

[Yardpilot]

My truck has a rear mounted tank and side mounted tanks. I only use the rear tank, at least so far. I would like to use them all. One of the tanks is capless. Neither has been used in years. It was like that when I got it. What should I do about getting these tanks ready? I'm thinking pull them, clean thoroughly, pressure test, replace any gaskets, grommets, fuel lines, etc. Is that too much to do? There is a manual valve on the cab floor. Don't know about sending unit(s).

[Beagle]

CLR (caustic soda, Lye) is pretty good for light rust / crap in the tanks. I'd halfass consider washing it with some swimming pool acid and rinsing it out really well. E85 would be good to get the varnish off maybe. I'd put an extra fuel filter on it for a while and consider a spare in the glove box for insurance. Checking the lines seems like a very good idea. There's some sealer kits for bike tanks, but it's pricey. I'd bet you could get poly replacement tanks for cheaper than spending a lot of time/money on the existing ones. LMC might be a good source for those.