I like the ideas about marking with a ribbon or tie through any item with a hole. I have my small scissors on a neck loop, and wear them. My scissors are marked with a sharpie, and I haven't had any problem not being able to read the markings, as I used a colored sharpie.
After one class I taught, a lady called and said she was missing a foot from her machine... That threw me. Why would that go missing? Two months she called, and told me she had located it - whew! I'm glad it was not someone else in class.