Deaccessioning and selling of museum items can have legal ramifications with the donor and the IRS. If you cannot afford a lawyer at least get a copy of ” A Legal Primer on Managing Museum Collections” Marie C. Malaro and Ildiko Pogany DeAngelis, third edition. This book should be one that all museum directors and collection managers have and read. It is a great resource on managing collections and will give you case law on what the courts are ruling in regards to such matters. They suggest you get a lawyer as well, but it is the best place to start.