Rehydrating Specimens

You can make a relaxing chamber using a tupperware container, a small plastic lid, some paper towels, and a bit of water. Get a couple paper towels and get them wet. Place them in the tupperware. Put the bup on the lid and place that in the tupperware (don't let it touch the paper towels). Close it up and in a couple/few days it should be good to go. You'll want to keep an eye on it so it doesn't get moldy. If you're worried about mold, you can add a few drops of mouthwash (the kind with alcohol in it).

Another method is to get a glass of hot water and set the bup in it, submerging it a few times. But that's one where things have higher potential to go wrong and the specimen can fall apart. It has the perk of being faster, but I'd probably get the hang of it with dead and dry beetles you find in the garage that you don't care as much about or don't intend to put in your collection.