FortuneCookie posted...
Technically, "Mickey Mouse" is not
Mickey Mouse, the name, is also in the public domain in terms of copyright law. The gray area comes from the fact that Mickey Mouse is a registered trademark, and trademarks don't expire. However, they also only apply in specific types of litigation. As I am not a lawyer, I can't say anything else with confidence.
Mickey Mouse, the name, did appear in Steamboat Willie, though. So the name is included in the public domain. It's just tricky to use it because of complications due to trademarks being different from copyright.