Professor
路My son has the Jonathan Arther Ciener .22LR conversion kit for his AR-15, and I have the CMMG .22LR conversion kit for mine. But they're more for the Zombie apocalypse if .223 or 5.56 ammo gets hard to find, since .22LR is so dirty.
Have you tried CCI Stingers? They work great in my Marlin and leave less residue than other brands I've tried.
Unplated lead bullet .22 LR leaves nearly as much vaporized lead as burnt powder in the action of a blowback and the lead is harder to get rid of. powder fouling will disolve in solvents and canned air will blast it out of nooks and crannies but atomized lead must be physically removed.