How do YOU index your vast array of thumb drives?

I try to buy different brands and different colored sleeves. I have music, audiobooks, sermons, pictures, work, and backups. They are usually in one drawer, except the music ones in the car,but are getting out of hand. Didn't think of movies yet, might have to look into that. Maybe white heat shrink tubing and a sharpy. That way you could change them if you wanted.