The best way I found as someone else has suggested is to just blow as much juice into a paper towel (out the connector end) & fill it with fresh juice.
Also I try not to mix to many different flavors in the Attys.
I try to keep them in families. I.E. Choclates, Menthols, Tobaccos, etc. seperate from each other.
I wouldn't use alcohol in my Atty's. It would be like washing out my coffee pot with soap.
It gets it clean but doesn't taste to good. :-)
Frank