If you use waterbase paint and poly it is not messsy at all. I use 1/2" PVC instead of 3/4". Less volume. And, I use a cheap turkey baster to draw paint or poly from the can, because pouring it IS a messy task, put it in the dip tube, and then pour the unused portions back into their original containers. With the 1/2" pipe and 11/32 shafts, you can let the fluid get pretty low before having to add more. As you drop the shaft into the tube it forces the liquid up the tube and into the reducer as overflow occurs.