Stamping on Playing Cards?

[Xiphoid Process]

So I had a great idea for making business cards the other day: Using a stamp on the back of playing cards! I made a stamp out of craft foam (cut the words out on a thin piece, glued that to a thick piece, so you paint it and the background is what is stamped, the letters are uninked...if you know what I mean, I hope!). And then I just grabbed some foam sponge paint-spreader thingies and used acrylic paint.

BUT THEN THERE WAS A PROBLEM.
When I stamped on regular old paper it looked super cool and all, but when I went to go stamp on the back of my playing cards the smaller letters were pretty illegible and blobby. I know this is because of the cards being plastic-coated, but I couldn't for the life of me find any uncoated ones.

SO I'M WONDERING...
Is there any way I can salvage the coated cards? I read once that you can mix some school glue with acrylic or PVA paint and then it sticks to plastic better...or could I sand the cards lightly with some fine grit sandpaper? Or is there any way to peel the plastic coating off? Or do I need to scrap this and use proper paint/paper/what-have-you?

Has anyone stamped on playing cards before? Help please and make a sad crafter happy again :-(

[Dayeseye]

I say try sanding them slightly with a fine grit, apply 2 coats of gesso...it comes in clear if you still want to see the design through, sand lightly again, tack cloth it and stamp away!

Good luck, can't wait to see the finished product! 

[thinkum]

Were you able to salvage the coated cards?  I'm curious to know how this worked out for you, and what the finished product looked like if you were successful...  :-)