The salt that most soft plastic makers use is call Quick Salt. I know Morton's make it; the salt grain is finer then table salt or the N/I salt. This type of salt is used to cure meats, for ex. jerky. I have tried table and the Quick salt, and the quick salt stays on the plastic a lot better. I also buy cooking spray, garlic favor, and spray the plastics down with it, then dumped a bunch of salt into the bag. Then let stew!!! Morton's quick salt comes in 2.5 lb and 5.0 lb bags; I have found it at Meijers, Kroger's and Farmer Jacks.