Yes the air cleaner uses engine oil, and yes, you can wash out the top section in solvent. The upper section uses aluminum wool as a filter element, I believe, and it's definitely washable. Let it drip dry thoroughly before restarting the engine, though. Back in the bad old days, a friend washed his air cleaner in gasoline, reinstalled it wet, and got a serious over-rev condition when he fired it up! The fast idle cam for the automatic choke was in the topped-out position, and those gas vapors made it rev up enough to make the rods rattle.
Jerry
