Farmer Focus: Could closed system end grassweed infiltration?

We are already pedantic about cleaning the combine between crops, we spray out fence lines and field margins and control grassweeds right throughout the rotation. There is no way we could expect a baler to be cleaned to the standard of our combine cleanouts, no matter how conscientious the contractor may be. So we have purchased a 4x3 Massey Ferguson baler, and I have had my first three lessons on just how hard a baler is to clean completely. [Extracted from the article]