On Oct 26 2004, 12:55, John Foust wrote: is, That's the CaCl in it, and there's usually not much. Calcium chloride is not merely hygroscopic but deliquescent. It's "use once" -- you can't really dry it off again, effectively. If you don't mind a liquid, concentrated sulphuric acid is a more active dessicant than either silca gel or calcium chloride ;-) Phosphorus pentoxide is good too, and doesn't get wet and sticky. Pricey, though! For a different reason, though. There's a slow double-decomposition reaction between the calcium carbonate in the shell and the sodium silicate (water glass) which leaves a layer of relatively impermeable calcium silicate on the eggshell. Sodium silicate isn't a drying agent. The drying action of silica gel (silicon dioxide) is due to adsorbtion, a purely physical (and easily reversible) process. Water molecules stick to the surface of the silica. The granules are extremely porous on a microscopic scale so they can have quite a lot of water adhering to them. -- Pete Peter Turnbull Network Manager University of York