I just tried your cup still. I used a Heat Lamp and a bottle of contact lens saline solution. It works more or less o.k. I haven't pursued it to a salt encrusted cup and Perrier in the Ziplock yet. The only obstacle is size. If you have the time to create a functioning still to treat a contaminated water source, you might just as well fashion a full sized one. I think I'd sweat a cup of body fluid at least just watching in anticipation! It would be a great training aid though.<br><br>