trying to remove gas tank liner

I'm attempting to clean out another gas tank . this one was coated with something different . it almost looks like acrylic or something like that , it's kind of transparent. So far I have tried acetone ,M E K ,lacquer thinner ,paint stripper and muriatic acid. None of touched this stuff !! When I try to pry the coating off it breaks in pieces ,all most snaps like glass. there too much of it to be able to scrape it off . I really don't want to have to cut out the bottom of the tank . Any help is appreciated , thanks

Do you have access to methylene chloride paint stripper?  That's what I've used.  It's super nasty, and you need to leave it for a while for it to work.  Sorry if you already tried this, you did mention trying paint stripper.

Good luck

Sounds like it is Caswel epoxi tank liner. Look for something that desolves hardened epoxi.

from the old kzrider. a radiator shop is an option. they'll dunk the fuel tank in a chem bath. but of course that would also remove the paint. I've never had this done.

You can try thermal dynamics.
Put the tank in the sun for a day.
Then put in a chest freezer.
try a couple expand/shrink cycles?

Maybe not the best idea, but if you're stripping inside and out, you can put the whole tank in a propane grill. outside. in a grill no longer used for food. It'll remove all the non-metal stuff. though take care to not overheat the metal and change the structure.