they clog up but with 500 of them and an ultrasonic cleaner I bet they last a long time.
I imagine you after a plague, or zombies, or war, in an enclave, 5 years later, panicking with only 2 spares left.
http://www.trackcap.com/
they clog up but with 500 of them and an ultrasonic cleaner I bet they last a long time.