John,
From what I have learned throughout the years from competent gunsmiths, it is virtually impossible to remove "all traces" of moly from the inside of a barrel. Of course the more shots that are passed through, the more difficult it is to clean.
As for what solvents to use, I'm really not certain because I never use such solvents. You may, however, wish to contact the people at Jarrett rifles, and also Hill Country Rifles. They may tell you their experiences with moly coated bullets in general, and what solvents to use in specific.
Zachary
