I found in a science catalog that if you put a little salt in your alcohol stove you can actually see the flame. I haven't tried it yet but when I do I will let all of you know what I found out. I don't think it would stop up the holes on my trancia stove.

I think you'll have to put a little water in your alcohol to disolve the salt so you wind up with a solution of alcohol, water, and sodium chloride. The sodium will give the flame a characteristic yellow to orangish yellow color. Other metal salts (copper sulfate, barium, stromnium, etc) will give you other colors. But AFAIK, none of those are soluable in alcohol.