Lego Keychain Removal

A couple of weeks ago I go a lego captain rex keychain. I know people who have taken it but I did not know how to. The reason I wanted to do this is so I could remove his head and put his battle armer on him. So after so searching I found one way to do this on flicker. My dad and I were not strong enough to do this though so after some more searching I found this way that was a lot easier way that I could do.