Sorry my stupid phone types all crazy when I'm on the forums. I usually put them into left over and cleaned wide mouth syle Pasta jars but you can use canning jars as well. They do usually end up forming a seal but personally I wouldn't dare leave them out a room temp since they haven't been processed in a canner or pressure cooker.Yes Put Lids On TheM. They Do Usually Seal On TheIr Own But I Always Keep TheM In The Fridge.