As is the nature of handmade soap, I think you're going to have to leave them unsealed, even though they are salt bars. Unfortunately, I don't think you should be sealing them, but I do agree with the shrink bands with labels applied to the band. That is easy enough to re-blast with the heat gun should they shrink a bit. Just going to have to store them in the least humid part of the house :/ Which yes, the humidity sucks most of the summer. When mine were in my house, they were fine, even at 70-80% humidity in the house, but when left out in the garage they did sweat.