Follows is a link to a transcript of a podcast about musical instrument restoration with a discussion about the specific problems related to pipe organs in particular...
http://www.ncptt.nps.gov/podcast-john-watson-on-the-philosophy-of-in-use-musical-instrument-conservation/ (http://www.ncptt.nps.gov/podcast-john-watson-on-the-philosophy-of-in-use-musical-instrument-conservation/)
Eric
KB7DQH