Those little packets that seem to come in all pill bottles, and a myriad other products, contain a desiccant, moisture absorbing beads. Usually known by the name “Silica-Gel”, these little packets are ideal for drying used hooks and flies, and keeping them dry.
Placing one in your fly box will help stop fly-hooks rusting, and fur and feather detiorating. I have a small, lidded box with two or three packets of Silica-Gel inside, into which I drop wet flies. By the time I get home the flies are dry and ready to go back into their fly-box.
And once safe and secure, I add a couple of the gel packs to ensure the flies in my fly boxes do not rust.
I also have a small lidded box for my used salt-water hooks. A couple of Silica-Gel packets in the box stops salt-water doing any mischief.
Used Silica-Gel packets can be ‘refreshed and renewed’ by ‘cooking’ them in a microwave for ten or twenty seconds. If you need more Silica-Gel, good places to try are, camera stores, garden supplies, dried flower supplies, and local pharmacy.