A while back my friend Bob was clearing his basement and found a load of old hand-cut signage stencils which had come from the Greyhound Bus Depot at the bottom of Potrero Hill - now the San Francisco campus for CCA. He handed them all over to me - naturally! I've been using them for a while but have only recently noticed the backsides of some of them. They have been cut out of old advertising panels. I love the interaction of the printed text and the reversed cut-out text. The top cut-out says "no steam cleaning in this section", and the lower one reads" keep out".