What kind of tank? If it's a plastic tank, no amount of cleaning may remove the flavor.
Yeah that's just the thing about plastics. No matter how good they are. Once a strong flavor impregnates the surface of the plastic, its there to stay.
Only a few options to deal with it.
- Get more tanks and dedicate them to the flavor or to extremely similar flavor profiles, or use stainless steel or glass tanks.
Another thing to keep in mind is that O rings will also absorb flavors and retain them as well.
EDIT:
Anyway, I forgot about the ultrasonic cleaners. I'm definitely in the market for one despite what I just wrote, probably one of the kind that goes 35W to 50W.
What most guys seem to do who use them is fill them with water, add a little vodka and let them run for a while. Considering that they can be had for under $50, I figure why the hell not?
At worst I'll find it doesn't do a better job than I can manually, but it'll be as effortless as pouring liquids into the tank, dropping parts into it and hitting a button....
....and I'm all about making my life easier.