Thanks Phat, I always thought that it was the stove-never ocurred to me it was the bottle.

I have two old bottles- an MSR and a Sigg bottle, and I don't remember the few times I put meths in one of them, which one I used. My MSR bottle is not one of the red ones, so that tells you it's pretty old. The outside of it is somewhat corroded-probably by salt air, but I just looked inside it with a small LED flashlight and the inside looks okay. The Sigg has fuel in it, so I didn't look inside it, but the outside is fine other than a few dents.

I also have a newer Brunton bottle-it looks like it has some kind of coating inside it, which the MSR doesn't.

The problem I had was that alcohol in a stove like an XGK gets used up really quickly because it doesn't burn as hot as white gas/Coleman fuel. You will lose the advantage of the stove design by not using the hottest fuel you can safely use.

I suppose if you really wanted to burn alcohol in an XGK, just get a coated bottle for the pump and use something else to carry extra fuel.