Is there a tool to remove a shell-extension? I was able to remove some context-menus using RegEdit but doing a search in the registry for others have failed.
A great tool that makes removing (or just disabling) shell-extensions easier is ShellExView. Use the mark options and sort on the various columns to help quickly cut through the clutter.
As well, Autoruns displays shell-extensions in the Explorer tab. Again, use the hide options to reduce false-positives.
If you are specifically trying to get rid of a context-menu, it may not actually be a shell-extensions; in which case, try ShellMenuView which makes it easy to manage such items.