One of my Old Guy medicines has an elaborate desiccant container:

Being that type of Old Guy, I weighed the container when I emptied the bottle, then left it sit in the kitchen cabinet with the scale for a week as the weight slowly increased.
It started at 2.38 g and stabilized at 2.56 g, so it absorbed 0.18 g of water from the air after it got my attention.
Peeling the label revealed an obvious joint:

Looks like HO-scale coal in there!
The desiccant weighs all of 1.20 g, so it absorbed something more than 10% of its weight. That’s less than I found with silica gel, but I don’t know the starting weight or how much moisture it already absorbed.
A newly opened pill bottle disgorged a container weighing 2.42 g. The initial weight obviously depends on many variables, none of which would be tightly controlled.


















