Paradiseair, I was told once by a Copeland representative that even in the deepest vacuum, Poe oil can still retain moisture and the only true way to remove all the moisture was to change filter driers, or have a oil filter in a oil return line (if possible)
Also, alco has a moisture indicator (sight glass)that will change color with respect to ppm of water and liquid line temperature, total ppm is figured out by using the graph supplied with sight glass.