As a video production teacher I was always labeling new equipment. The equipment was expensive so I wanted to make sure my labels were clear as well as permanent so that I could stay organized and things wouldn’t’ get stolen.
The photography teacher at my school used nail polish to label his cameras and I quickly adopted it! I recently used it to label all the equipment for Backlot Film Camp. It is awesome because you can use any color so that it stands out against whatever surface you have to work with, and it won’t wear off.