Thanks for the response guys!
I was told a rinse and dry burn was sufficient, but on digging around online forums, some say this method doesn't completely get rid of the previous flavor and can ruin the taste and experience of any new flavor that you subsequently vape. I guess it depends on which flavor was vaped beforehand and I should keep separate tanks for different groups of flavor? For example, it would be difficult getting rid of menthol! I wonder whether it is feasible to sterilise them...
Anyhow I'll give it a try and see how I go.