I have used those as well (in pocket-sized kits) with pretty decent success. The trick is to be careful when folding and unfolding so you don't wear a hole in them. I would choose these over foil any day but they would never replace a good metal cup like the one I mentioned above. If I have room for the cup then it goes. If not then these go. If there's no room for these... well then I have a thread here somewhere on primitive pottery in 8 hours or less. <img src="/images/graemlins/wink.gif" alt="" /> I'm still working on that one by the way, for those who are keeping score. <img src="/images/graemlins/grin.gif" alt="" />
Learn to improvise everything.