I tried a few things over the years but last year I finally broke down and built a simple parts washer out of an old stainless sink, it's got a 5 gallon bucket under the drain and uses a cheap Amazon special parts washer pump. I'm using some solvent I bought from tractor supply that's like mineral spirits but works a lot better. It's kinda pokey compared to the automatic ones but it's handy to have for little stuff and melts off grease and oil like nothin.
If you really want them nice and clean you can't beat vapor blasting. It cost me about 75 bucks for a whole e50 a few years ago, then shipping both ways, it adds up. Tough to justify for most of the junk I build.