Hey, Rich. Nice to meet you man. I'm new to vaping so I can't say for sure. But as far as I know you can't clean out a pre-filled cartomizer. But it seems like you would be able to vape it until it's empty and then fill it with a different flavor. I'm sure the original flavor would linger for a few cycles but eventually then new flavor would over-power the old. Just a guess though. If you try it let me know how it turns out man! I'll be trying it too because my brother hooked me up with some cartomizers he bought and didn't like, and I would like to try and fill them with some different flavors without having to buy blank cartomizers when I already have like 10 free ones!