Some other threads were saying a fair bit of water in glow fuel doesn't hurt anything. Even 5%. I have had a lot of stale fuel problems because of running .049's and .15's all year. One quart gives almost a years flying. I saw a full tank of fuel in a tank go to about a quarter in about 2 years,(too lazy to empty it) so I suspect the methanol and nitro is evaporating out, giving the stale fuel. A glass jar also did this with some 40% that I mixed up too. A metal container is better than plastic too. I just run a .40 control line plane to use up my stale fuel, It is hard to start but doesn't need to idle. Like cutaway says , you can mix it sparingly with other fuels. You could also add methanol/nitro mix to freshen it up, but you wouldn't know how much oil is really in the fuel. Sometimes diesels need a little shot of ether to freshen up in this way.
As far as getting water out of fuel, and I will add that I haven't tried it, You could try freezing it in the freezer and filter it through a coffee filter when the water settles to the bottom. I don't think this will cure stale overevaporated fuel, but may get water out, (maybe not, but you will have filtered fuel anyway)re"> OK let's hear some other opinions and experiments on the freezing/filtering idea now. I can't do it now I'm on a holiday.