Product for dissolving gum in fuel tank

[mmkkpro]

Hey guys, I am cleaning my tank today and its pretty bad. I can remove the solids off the liner fairly easy, and there is a lot. My question is how to remove the gummy varnish that has accumulated. I have read a few posts that suggest white vinegar and baking soda and water and another that suggests draino , I don't want to damage the liner in the tank, thanks.