We are new to this area (Northern Territory, Australia) and I'm wondering if the high chlorine or calcium levels play a part as well. Speaking of which, I'm used to dealing with kettles going black, but here they go white!!!! Any ideas?
JiK has done it again with the serious info but, in Oz, you can buy from most supermarkets a product named "CLR" (for Calcium, Lime & Rust) which is designed to remove the scale that deposits the preciptated magnesium and calcium salts disssolved in the bore water intil it's boiled.
Bee, the gunge in the bottom of your camp oven is polymerised oil and is usually removed mechanically. When 'proving' cast iron cookware a thin film of oil is sufficient.