1 Monty: I can't believe that guy was selling mummies. Like they were commodities!
2 Minnesota Jones: Yes, they're all meticulously prepared by hand. Embalmed with fragrant oils and unguents to preserve the skin.
3 Minnesota Jones: The organs removed and stored in canopic jars. Then the body filled with natron salts in a solemn religious ceremony.
4 Prof. Jones: I always wondered why the liturgical part was necessary.
4 Minnesota Jones: They had to make sure they had the Rite Stuffing.

Natron is a naturally occurring mixture of salts, mostly hydrated sodium carbonate with some sodium bicarbonate and traces of other sodium salts. It's typically found in dried up lake and river beds.

The word natron comes from Wadi El Natrun the place in Egypt where the ancient Egyptians mined the salts for use in preserving bodies for mummification. They referred to the salts as ntry. This passed into Ancient Greek as νίτρον (nitron), and thence into Latin as natrium. And this is why the chemical symbol for sodium is Na - it comes from the Latin, but ultimately derives from Ancient Egyptian. How cool is that?