Marking your microphones (or other gear..)

[amra]

How do you guys keep track of your mics?

For example I recorded a band and they brought over their own SM57's - there were '57s all over the place. I kinda had to be a dick about it to keep mine straight. I have thought about engraving my initials or some other identifying mark on my gear, but then if I decide to sell them later this might hurt their value. How do you handle this?

 

[cpl_crud]

If it's a simple situation like that, hte white electrical tape and a sharpie.
Industry standards in marking.