Technical Hardened gas sludge in tank. Can I break it down?

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Let the car sit for 7 years.
The gas was drained and this residue and very caked on gas was the result.

So far. Acetone has not touched it. Even a bristle brush and acetone hasn't removed it from the sending unit as it is very hardened.

What breaks down hardened gas like this. The tank was basically new and should be shiny in there under all that hardened varnish.

Please advise

 

I have had success breaking that down with Varsol, parts washer solvent. You can usually get it at parts stores or Tractor supply. Just let it soak for a few days.

 

I tried a lot of things including chains and rocks inside while strapped to a tractor riding around and finally used POR15 to coat the curds of old gas. Thats been 22 years ago and I dont get any other trash in my fuel filter

 

Pull it and take it to your local radiator shop and let them hot vat it overnight,it will be as clean as a whistle. HRP