Put some de-natured alcohol in it, then add the gas to your car tank. should burn fine.

Last autumn being like 9/07? If you had stabilizer in it you will be OK, if not it's somewhat risky but I would try it in something non-essential. Not for trial in a generator.

There may be water in the bottom so don't shake the can when you pour off the first 4 gallons, check the last gallon for water.

Look in it, is there anything in there other than gas? Pour some out, is it clear (or close to it)? Does it smell ok?

If there isn't any particulate matter, its clear or slightly yellow and smells alright, then I would add some dry gas and run it mixed with "good" gas in anything. I do this all the time for my dad, he will have 6-9 month old gas, normally a gallon or two. If it passes the tests above I will put it in a 5 gallon container, add some dry gas and go to the store to top it off with 2-3 gallons of premium. I don't do it so much to save money but rather so I don't have to dispose of a couple gallons of gas.

I burn it this way in my snowblower, snowmobile, lawn tractor, push mower...pretty much anything except the weedwacker and the chainsaw.

The enemy of gas is heat vs cold. It's fine but I would throw in a can of de-icer in case condensation has formed.