Nate,
If you can get hold of an caustic soda based oven cleaner, here in Ireland I use Mr Muscle brand, put the part in an old plastic container, spray on some oven cleaner, close the lid and leave it over night, you'll find a perfectly clean clear part the next day. I've used this to strip 15 year-old enamel off canopies, no problem. You may need to give a light rub with an old toothbrush over the sink, but that's all. Modelstrip is also a good product, but I don't know if it's available in your part of the world?
Cheers,
Roy