You're right, iBill, it's the vapours that are the problem with fuel. Nylon clothes are probably a bigger threat to safety as a static build-up can cause quite and interesting spark. The vapour has to be there to ignite, of course.
I had a lovingly cared for stamp collection. As a kid, I spend a small fortune of my pocket money. I had, what I thought, were a few valuable stamps. Turns out they are worth, just as you said, very little. I really cannot remember what happened to them. I might have put them back into the roof space. I guess i'll come across them one day.
As with all these things, they are only worth what people will pay, and if they are not in vogue, either put 'em back in the storage, or hand 'em down the line.
I have a friend that collects old toy cars. His collection is valuable because these are the rare vehicles, mostly pre-fifties, and there's a good collectors network. Some of these vehicles are worth many hundreds of $. He has many hundreds of these cars.