A list of your installed plugins can be obtained from about:plugins. As a general rule, to remove a plugin, you remove the file listed in about:plugins for it. For plugins installed by hand, check the appropriate PluginDoc page for any other files to delete.
Additional steps may be required for the following:
Mozilla Firefox looks for plugins under the Mozilla profiles directory instead of its own profiles directory. If you want to remove a plugin for Mozilla Firefox, but not Mozilla, you will have to relocate it to the plugins directory of your Mozilla installation (Bug 172891).
To stop your browser from detecting Macromedia Flash, Adobe Acrobat Reader, QuickTime, Windows Media Player or plugins installed for Netscape 4.x, you may have to edit your plugin scanning settings. More information about plugin scanning.
Removing the default plugin will stop you being notified if you require a plugin to view embedded content.
Removing Macromedia Flash may require you to delete flashplayer.xpt from either the plugins or components directory of your browser.
RealPlayer 8.0, RealOne Player
Removing RealPlayer 8.0 or RealOne Player may require you to delete nppl3260.xpt from either the plugins or components directory of your browser.
To configure or remove plugins installed using CrossOver Office, launch Office Setup and use the Plugins tab.