It's come up in several threads whether or not Bovedas can be brought back to life once they dry out. I'm not sure if you're "supposed" to or not and the Boveda website mentions nothing about it (that I can find). However, I've been doing it for about a year and a half now and I know others have been doing it longer with no ill effects to the humidity regulating properties of the Boveda pack. So here's how I do it...
What you'll need:
You'll need something airtight to revive the Bovedas in. I use a plastic canister. You may also use a Tupperware or similar container. The biggest concern is that it is airtight. One or more shot glasses or similar container. A couple paper towels. Distilled water. Desiccated Bovedas.
Fold up the paper towels and stuff them in the shot glasses. I fold mine so that they fan out a little. This increases the surface area for the water to evaporate from and I've found it speeds up the process versus just filling a shot glass with water.
Fill shot glasses with water and allow paper towels to soak it up. Then top it off (careful not to get too close to the top though or it'll spill easily).
Place shot glasses in airtight container with Bovedas. Let it sit until they're squishy again. Different RH will require a shorter or longer time to rehydrate. I toss different RH in together, the lower RH will be done first (i.e. 65% before 70%).
Once they're completely squishy, use 'em or put 'em in a plastic bag (I prefer freezer bags with the double seal and double bag, but maybe I'm paranoid) until you need them. Works best if you have a cycle where some are hydrating while you're using the others.
Hope that helps everyone with questions about this. If anyone does it different or has some other tips they'd like to share, fire away!