It's summertime, and that means cheap pool noodles at the store! In honor of the terrible, horrific, scary posting at diydrones about prop injuries, here's a method a lot of people use when working on their quads.
Slice out a section, and it will fit nicely over your props. If you accidentally power them up, they'll shake and shudder alarmingly in the noodle, giving you plenty of time to pull the plug.
See it shimmy and shake in the most shocking manner!