Article: In Safari, add-ons are referred to as "plug-ins". Click Help Installed Plug-ins. This will open a new page that lists all of your installed plug-ins. You will be shown the file name for the plug-in (for example the QuickTime file is called "QuickTime Plugin.plugin"). You won't be able to uninstall the plug-in from within Safari, so make note of the file name. OS X has hidden the Library folder, which is where the add-on files are stored. You will need to unhide the Library folder to find the plug-in file. Open your Home folder in Finder. Click View Show View Options. Check the "Show Library Folder" box. Refer to the file that you noted in Step 2. Navigate to the folders that contain the plug-in files. The plug-in files may be located at Library/Internet Plug-Ins/ or ~/Library/Internet Plug-ins/. Click and drag the plug-in file to the Trash. Restart Safari for your changes to take effect.

What is a summary?
Open your list of installed plug-ins. Find the plug-in you want to remove. Enable your Library folder. Find the plug-in file that you want to remove. Delete the file.