Quick story..
I had a friend who bought a Box of these Mexican lobby cards at a flea market in Laredo and called me
Saying he had found a cache of rare movie posters.....Casablanca, Tarzan, maltese falcon, king kong, Abbott and Costello etc..I told him I would take a look...
When we started going through them...we found dozens of the best cards completely mutilated by grease pencil mustaches on the women.....drawn on boobs, a beard on Ingrid Bergman, wieners drawn on faces.....etc....about 75% of them in fact were written on in some way...
I have talked to several other collectors who had the same experience...