Hi Shannon,
I know your post is a few years old now, but this is something I am now researching for the Development department at the Museum of Flight. We are finally doing an overhaul and cleaning up of our own donor files as some go back to the 80's. Our files used to be on the same floor as us but now reside in the basement. The only really clear note so far is we keep the acknowledgement letters/thank You's for gifts over $250. We are currently removing the memorial folders, and all deceased individuals before 2014 (we are keeping all documents within the past 7 years for auditing purposes). My supervisor has posed a recent question of "Do we need to keep paper copies? Or can we digitize?".
I hope to find some more policies and procedures from other organizations.
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Freyja Lye-Kordich
Development Associate
The Museum of Flight
Seattle WA
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