I use a large bowl type tupper with a smaller one in the bottom with distilled water in it. I took an old refrigerator grate and cut it to fit over the lower (water holding) bowl and lay the Bovedas on that. I have had 10-12 in at one time but it takes longer to recharge. Some say you can put them in or on water but I never make contact. I pull when I start to feel chunks and stick them in to recharge. I flip them every day or two and "massage" them to mix the liquid and chunks around and get them to dissolve. I pull them out when they look good and the chunks are gone but I don't know that they are exact to the RH that's on the pack. My guess would be they lose a little over time so I don't worry too much about it, but the short answer to the original question is hell yeah. I've got packs 3-4 years old and have no intention of changing them out yet.