Just received my first Kayfun (EHpro Lite +) on Monday. What I do with mine, is take my syringe with a 16ga blunt tip (16ga is just what I generally use, not particular for it) and pull the juice out. Gets nearly everything out. Then unthread the entire tank section while holding horizontal... What little is left will stay in the tank as long as it's sat on it's side.
Obviously, being able to thread everything off and leave the tank upside down like a Protank would be easier, but I don't find this challenging. Hell, I've even done it with a small tipped bottle... Just pre-squeeze it, place into fill hole, and let the suction do it's thing. Syringe is more efficient though.
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