Holding onto Unreviewed Review Books

It's become crisis point space-wise here at Euro Crime HQ. The books are everywhere and I need to make a cull.

What happens with review books is this:

Books are sent direct to me as co-ordinator of the website and roughly once a week I email a list of received books with synopsis to the review team. They email back with their preferred choices, I post the books to them and await the reviews. I also get emails from publicists who ask about a review for a particular title and I circulate the details and get the book sent direct to the reviewer (this is preferable to me as it speeds the process up and saves me £££ on postage).

But the thing is - what to do with the books nobody has requested? How long do I hold on to them? Do I hope that someone's enthusiasm will be pricked by a review from another source or perhaps that a new reviewer will join the team who might have different interests?

Does there come a point when a review of a book is too late in the day and that slot would be better given to a newer book?

What do other review sites do? Do they send out books on a pot-luck basis to their reviewers and does this generate more reviews or less if you've not been given a choice as to which books you want to review.

Do publicists care/notice if you don't review every book they send, on the site and would they find it preferable, though time-consuming, for books not to be sent until a home is found ie do everything by email first.

This same quandary about hanging onto books applies to one's own to-be-read pile. When do you say - I'm never going to read that book? and thus rehome it.

One final point is that I also get a small number a week of what I call American serial killer books and unfortunately, they are not covered under euro crime so I donate these either to a fellow blogger or my library.

Any thoughts on the above, from reader, reviewer or publicist, welcomed :).