Script Summary: A simple script that removes unwanted clutter on YouTube pages. What makes it special is that it includes controls to restore them instantly.
This will remove the comments, related videos, promoted videos, sharing information, and footer from Youtube. The latest version now includes options in Greasemonkey's user script commands menu to unhide them. It even saves your preferences automatically!
If you have any requests feel free to post a comment below and I'll see what I can do.