A wife works pretty well
I have an MT75 alloy box, I did that with a rotary wire brush in the drill, took ages to get in all the little nooks and crannies. The engine was cleaned with the same, some gunk and a hand held wore brush. Gunk stinks, it gets in to your skin and you smell funny for a week. Having said that it's cheaper than after shave and much more manly to boot