Need to clean fuel tank

[Brads]

OK, I pulled the plastic gas tank on my Murray Ultra mower and it's got black tarry stuff all over the bottom. (varnished gas) What's the best way to clean that out? I've heard a lot of stuff. Put pinesol and old nuts and bolts in and shake it around. Or use kerosene... or xylenol, etc. Anybody know a way that works and won't hurt the tank? Thanks in advance :smile:

 

[Brads]

Update: OK, here's what I did. I pulled the tank off and put about a pint of Acetone thinner and a bunch of BB's in it. Sloshed it around for a couple of minutes and it was clean as a whistle. ALL the varnish was completely dissolved. Then I dumped out the thinner, (saving the BB's for another time) washed it out real good with water, rinsed it with a bit of gas to get any leftover water and put it back on. Works perfect now.

Caution: Acetone is really harsh stuff so if you do this, don't leave it in too long as it may eat away at the plastic. Lacquer Thinner or maybe even Paint Thinner might work too. It would just take longer to dissolve the varnish.