I used Berryman Chem Dip from Autozone on 2 engines recently and its very good on these parts. Yes if left too long in one session it will turn parts gray but you can bead blast them or use soda blast etc if that happens to brighten them back up. it takes very little time and the parts come out bright again. I did a Saito FG36 and an OS FS120 with this stuff.

The ultrasonic bath is also very good and you can clean your jewelry in it as well, earn good wife points there (just no stones!!!). The ultrasound bath is heated and there are different solvents that clean effectively.