Hmm this came up the other day.

I work in Time Tunnel Models and we were going to get the XBG out to check all was fine and dandy.

The Fuel we had been using for the past two years (or more) had changed colour, and looked/smelled very odd.

Not really having much respect for the crappy XBG we filled it up;

Started first time. The fuel reacted no differently. It had been stored out beneath the sink for the whole winter, so would've gotten damn cold.

Who knows how long fuel lasts? And at which point does it become unsafe? Well; two years and counting....

C.A.R.