Here's an interesting one. I'd always thought petrol to have a shelf life of 3 maybe 4 years max. I have an old jerry can with some unleaded from 1996 (chalk mark) which I usually use for cleaning stuph with.
Well (erm) I accidentally filled my Honda EU10i Genny with the contents...
Runs a treat! Certainly no noticable difference from the 'new' lot filled a month or so ago.
So, what determines the shelf life of petrol, anyone?
As an additional interesting aside, the jerry can it was in was the most rancid one I have, previously filled with all sorts, including Red Deisel for mi boat at one point. The only thing about that can that was 'new' was the rubber seal around the cap.