As a nipper, my mum would tell me that to make a bare-metal frying pan non-stick, all one had to do was cover the bottom in dry salt and heat it up to a very high temperature, then after a while discard the salt (somewhere safe coz it's hot!). Obviously this effect was only present until one used and washed the pan.
I wonder - has anyone else heard this? Would it work in a camping/open fire situation? It might save some washing up and is fairly environmentally sound.
I used to think this was to do with melting a tiny amount of salt as a coating onto the surface of the pan. Now, I'm not sure though as I found out to melt salt you need to reach over 800 degreesC while aluminium (we had cheap pans...) melts at about 650 degrees, which means the pan would melt and give a nice coating to the salt! So, instead I think it's just a clever heatproof abraisive that means the pan's nice and clean making it less sticky.