Though not quite a direct answer to your question, paper cups will work too. Place them directly on hot coals. The paper will not ignite because of the water in the cup. Boiling water will keep the paper cup at 212 degreed F., well blow the temperature needed for combustion.<br><br>Also, you can make good of other "containers" you may have around, orange rinds or onion shells. Be creative. You may be lucky enough to find a rock with a small hollow in it, but you might end up burning your lips when you try to sip from the hot rock!<br><br><br>BTW, cooking on rocks is fun to do. I've done small cubes of meat and even Bisquick biscuits on rocks. I haven't tried fish, but I'm sure it can be done. I'll have to try that some time. As Chris warned, don't chose river rocks or rocks at water's edge. The heat will turn the moisture trapped in tiny pores into steam and explode like popcorn, spreading rock shrapnel.<br><br><br>Willie Vannerson<br>McHenry, IL