To get rid of the release agent, I have been using Gojo hand cleaner.
It has orange oil, and pumice, and works great at removing the release agents, and prepping the parts for paint. I use a toothbrush to work into every nook and cranny, and throroughly rinse the pieces. And I mean throroughly. The pumice will get in every crack, but with some diligence, it can be removed.
My two cents, worth slightly less in Canada.