These are great comments! I’d just like to add that if you are collectiong something that doesn’t fit your mandate, you may be taking it away from someone whose mandate does include it. It’s important in a heritage community that everyone respect each other’s mandate. This is another explanation for donors of unwelcome material.
Another more vital fact is that it costs an institution to store, preserve, exhibit and make accessible every artifact and record on its premises. There is a cost per square metre/foot that an institution pays to keep that box of unwelcome books on a shelf, and it could be taking up space that another, more relevant donation may require. In the current climate of shrinking resources, I think we have to look at the issue from an economic perspective as well as a mandate one.
Thanks for the opportunity to comment.