Travis,
While I can't speak for the law in California, I thought I'd at least clue you in on things here in Oregon. While you are correct that the Supreme Court has ruled on garbage as public domain under the 4th amendment (California v. Greenwood), here in Oregon STATE LAW dictates that trash containers OWNED BY THE PARTY still maintain their privacy interest under Article 1 Section 9 of the Oregon Constitution (see State v. Galloway). Anything in those cans retain that same interest until such time that they are picked-up by trash collectors. At that point, they become public domain. Also, if you move, climb in, or even OPEN the top of the can, you could be infringing on that protected interest. It might well be the cops would just tell you to get lost, but I would hate to see you get nailed just because of a misplaced belief.
Good luck.