[psimet]

There was a great video on youtube at one point that showed how to clean it out fairly well. IIRC it involved like a gallon of acetone to dissolve all the varnish from the old gas. Rock it then drain through a painter's filter. Run a few gallons of gas through it, rocking it a bunch and then through more filters. Repeat until its fairly clean with no more residue or particles. then throw a pencil filter on the shutoff and run with it.

I did that with great results.