Our service has pretty much stopped taking donations for a number of reasons.
First off, we get offered some frankly quite dodgy, inciteful and sometimes downright offensive material. Librarians are a pretty open-minded bunch, but a line has to be drawn somewhere.
Secondly, we get offered books that are marked in some way - dedications in the front, a bit dog-eared, that sort of thing. People pay their council tax, among other things, in order that their library is stocked with the latest titles in good condition. Also, we feel that the poorest of our borrowers have just as much right to read new books as the more fortunate ones who can afford to buy them.
Thirdly, much of what we're offered just won't issue. It sits there taking up valuable shelf space that could be used to shelve faster moving stock. Not what you want too much of when library funding depends in part on the number of issues.
And fourthly, a lot of it is out of date. It's not such a problem with fiction, but non-fiction can date very quickly. It can be in perfect condition but still smack of 'old' - like a 1980s cookbook, for instance, and in some subjects out of date can be dangerous.
Lastly, for every ten library users that look at this list and say 'that's OK, I don't mind', there will be at least one who wants to know why their council tax is being spent on old/out of date/irrelevant stock or why, indeed, it's not being spent on stock at all.
Our policy now is that we can only accept donated stock if it is new, clean and of relevance to the community the library serves.