upon inspection of my "new"2x3 Pacemaker,I discovered mildew, mold, fungus or something similar inside the surface of the bellows. What is the best way to arrest this before it affects the lens? Thanks

I don't have a cure bout for starters, remove the lens board, ground glass frame, and extend the bellows to maximun. Let it set like this in a warm, dry place until the crud is a dry powder that will brush off.
Charles