Dropping the tank on my GL1000 was the first motorcycle wrenching I ever did. Once you concede that it's not coming out thru the top... it's just a matter of taking the tire/fender/etc off and it comes right out the back.
I'm a nurse (who at 42 had never ridden before) and I figured it out. I would guess that most others on the forum are better equipped than I was to tackle this issue.
I also refinish antiques, and am familiar with both NAPTHA and Denatured Alcohol. NAPTHA is a petroleum distillate like many of the others mentioned, but it is "cleaner" and more refined. It evaporates faster and leaves less residue than mineral spirits and other products mentioned.
This is a pic of the brand I prefer:
Denatured Alcohol is not the same as rubbing alcohol (isopropyl alcohol). Denatured Alcohol is essentially moonshine (ethanol) with a poison (usually methanol) added so it can't be consumed. The cleanest Denatured Alcohol I've used as a shellac solvent seems to be Kleen Strip's S-L-X brand.
It is available at most paint and home improvement stores. It evaporates with the least residue and funky smell of the Denatured Alcohol's I've sprayed.
I didn't mean to get too preachy or technical, just sharing my 2 cents.