Over at the Vintage Sports Card Blog there is a great article about Fleer Cards. When I lived in Philadelphia a few years ago, I would take the train from Center City to the Fern Rock station where my apartment was just around the corner. On the trips to Fern Rock, I made sure that I got a seat on the right side of the train. The reason was about 3 or 4 minutes before we would get to Fern Rock, the train would pass which looked like an abandoned building. But that building was distinct because It had the large words FLEER on it. My biggest regret when I was in Philadelphia was not going in search of that building. I am not exactly sure where it was but using google street level maps I was able to find it. It was right next to the train tracks at 5336 N. 10th Street. The sign states Fleer Gum. It appears the building is being used by another company but it was great that they kept the sign up.
The link to the map/photo is http://maps.google.com/maps?ll=40.033656,-75.139513&spn=0,0.0012&t=h&z=20&lci=com.panoramio.all&layer=c&cbll=40.033715,-75.139601&panoid=jvt2xMsf44rCbnxFjXyV4w&cbp=12,69.98,,0,-13.52