Firefox discovers that plugin through a registry entry that other programs use to advertise the availability of plugins. Since it is installed as part of Java, there isn't a separate uninstaller for it. If "Never Activate" isn't a satisfying way to make sure it stays disabled, you could physically delete the DLL file from disk. There's a good chance the next Java update will put it back, but if you want to do that for now, you can learn the location as follows: Type or paste '''about:plugins''' in the address bar and press Enter. This will load a long page of plugin details. If you search for ''toolkit'' you should be able to quickly find the Java Deployment Toolkit section.