Ephemera -- Prayer Cards

I order a steady supply of weird things from eBay.  Last year that included a packet of 25 or so sepia-colored vintage prayer cards.  They're small, about 3x4", and these date from the middle 1900's.  I'm collaging (desecrating?) them with some anatomical cuttings and other scraps, for a little book project I have in mind.  The cards are a centuries-old tradition in the Catholic Church.  They typically show a religious image on the front with a verse or prayer on the reverse, and are used to commemorate special moments (First Communion, Confirmation, funerals, etc.).  Many of them are quite beautiful.