I do something similar to what Dennis has above...likely got the idea from him...I use a "gasket" with my system, though...same pvc tubes, water based finish (or any, I guess), then a piece of tshirt as a gasket...dip down through a very small hole in tshirt and pull back up...basically eliminates waiting to drip, etc...quick, clean and easy...dip through tshirt, hang...repeat after a half hour, few hours, days, etc... depending on finish and how durable.
I use the "see through" caps for pvc and screw down the tshirt material when working, then some plastic to really seal when not working.