I was wondering if anyone else uses what I call a 'mutt' bottle. It's a used e-juice bottle that I empty my cartomizers in when I get tired of that flavor for the time being. I have so many different flavors in it that it constantly changes. It's sort of like a little adventure. I don't want to waste the juice. I want to know what other people do with a half filled cartomizer when they want to change flavors.