The best in my opinion is a high powered ultrasonic cleaner.
One of those soap packets that you mix with sulphuric acid followed with a base and limonene wash and 2x mutiple solvent mix(Tolulol,dcm,meoh,acetone,) works good for like frac.still pieces, flasks, traps, etc. (all this of course with an initial acetone then water water wash with rinses in between each phase and a water then acetone final to dry). If you buy plans for a ultrasonic generator and buy or build a power supply you can just mount it to one of those stainless buffet tubs with a lid. You can build one that is 12"Wx36"Lx12"d for the same price as a lil $300 jewelry cleaner. And if that doesn't get it clean or keep a forensic lab from piling evidence on you then nothing will.