I have not been able to fly much in the last two season.

As a result my glow fuel has been arround for 2 or 3 years.

Does glow fuel go stale or lose some component if kept too long after opening?

Fuel can last a very long time if kept in a cool, dry place - out of direct sunlight.

My uncle and I ran his plane on fuel that was at least 10 years old once - and the engine ran just fine.

Hold your fuel jug up to the light.  If you can see any kind of sediment/particles floating around in it then pitch it.
Otherwise, give it a try and see if your engine will run on it.

The stuff is too expensive to throw out unless you have to...   

Chuck

I also have a half gallon some really old fuel 10+years, and it just might run an engine.  But I chose to use a $20 bill for a new gallon and consider it cheap for confidence that my engine is not going to quit on takeoff or harm my engine because the oil has broken down in the fuel.  Just a mater if the few $ of fuel you have left is worth it to you...