Are you a mummy made of salt or are you a mummy that's salty about the whole dying and mummification thing?
Neither. Salt mummification is the best. Most liches have to deal with their bodies dying, rotting away, and then the constant hassle of trying to hold a skeleton together. My body on the other hand was mummified in the traditional Gulgathan manner using a salt mixture called "natron." It's a method we borrowed from the egyptians, but we usually cover our mummies in a layer of red clay as they mummify and we don't extract the organs. I just had to sit around in my little ball, wait the few months the process took, and then I could retake control and move it around. The only drawback is that everything tastes of salt.
So, wouldn't your corporeal form be destroyed by fire pretty easily? Such as that readily available from matches or found in the boiler of 19th century trains?