I would suggest that unclaimed prizes can be donated to Francis house. Its a childrens hospice in Manchester.

It is well known for the little girl, Kirsty, who is trying very hard to raise funds to secure its future as a Hospice for children.
The Hospice receives no funding from the local NHS or Goverment so all the money they have is fund raised.
All these funds are used to help the children during there last weeks/months/years of life to be as happy as possible by giving them makeovers, trips out shopping etc.
I think and probably plenty of people reading this will agree that the prizes could be raffled and the money raised could go towards the 5 million target they are trying to achieve, Kirsty then could be proud of all her hard work knowing that the target has been reached!