My friend just picked up some UFC's. They have some kind of hand applied (felt pen, Chinese brush?) marks on the edges. The marks seem to be competely random, different lengths and locations. These probably came from somewhere in the northwest.

This is the second time I've seen chips marked like this. The first time was a set I got (also UFC's) from Billings, Montana.

What are these marks? Why were they put on the chips, obviously well after manufacture? Thanks.