Solvent for cleaning oil pump and oil screen

I brush apply gasoline to remove most of the gunk from any carbon covered parts, then a final spray cleaning with carb cleaner. I once had a parts cleaning tank with a pump, and bought bulk solvent five gallons at a time from NAPA, but it didn't seem to work any better than gas. The water based material I tried the last time was nearly useless.

I don't do enough cleaning now to justify a tank, and I'm sure the EPA has outlawed all effective solvents for home use, so I do it the simple way.