Two years ago, I found an old pass from 1987 (also 6 day) with one day left on it. I also had read somewhere that it was only good at the parks that were in existence back then. So I used it on a day where I only hopped between MK and Epcot. Just used it at the turnstiles like any other ticket. At MK they had to scramble to find a stamp, since it was the kind that got stamped, then they opened the HC/stroller entrance to let me in. At the FP machines, I just showed my pass to a CM to show that it wasn't able to go through the machines, and they printed a FP out for me (Beware! Some CMs try to tease you that if your pass won't work, you're out of luck. Fortunately that didn't happen til I had gotten FP's several times). Same thing at Epcot, but CMs there were very interested in the pass, marveling at what it cost back then ($95 for 6 days)-it was a real conversation piece at the gates, but never a problem.