Unfortunately one of my batteries quit working last night. I have several unprotected 18650's that I ripped out of a laptop battery that unfortunately are going to have to suffice until I have some money to buy more.
I know the difference between the 2, I know the risks that unprotected batteries, but what should I look for before using such a battery?
I know the difference between the 2, I know the risks that unprotected batteries, but what should I look for before using such a battery?

Vapor's Rule Numero Uno "Backups for your backups!" Never depend upon one PV or only have one battery. Don't put yourself in a situation like the OP. Keep an inexpensive eGo for such an emergency. Don't resort to using inappropriate batteries. If worse comes to worse, run to the gas station or convenience market and grab a couple of disposable e-cigs until you can get more batteries.