As my mother would say, elbow grease: scrub a lot, and usually you get results. THe chemicals are secondary. Very secondary, in many cases.

Pigeon I've never done before... But it can't be So different from chicken, can it? Oh, I need my own old copy of Joy of COoking (that doesn't just have pigeon, it has things like racoon and squirrel. Thank goodness I can't/won't eat them.)