H,
If you have the time and still too many books, You could do as I did and take the most commonly axailable on your swaps list to the local charity shop or hospital.
I searched Readit Swapit for each title and if more than 5 others were trying to swap that book I took it off my swaps list. Some of my titles were also being swapped by over 100 other users.
Best of Luck, Mike (Stormbringer).