PREFACE: This post is an expansion (and paraphrasing) from questions asked to Dr. Mark Levitch, an art historian at the National Gallery of Art, and the founder and president of the World War I Memorial Inventory Project. He has partnered with the U.S. World War One Centennial Commission on 100 Cities/100 Memorials.
The most important thing to do is to leave any hands-on work to a professional conservator. Any attempt at "cleaning" a memorial—even a simple bronze plaque—can cause permanent damage. The American Institute for Conservation maintains a list of qualified object conservators. Non-professionals can focus on documenting a memorial photographically. You can pay special attention to problem areas, such as cracks in stone, graffiti, or discolored plaques and of course, it is always possible to put together a project that focuses on cleaning up or beautifying the area around the memorial, including landscaping, adding a place to site in contemplation, and things of that nature.
We also nvite you to join us for our "Memorial Restoration 101" webinar scheduled for September 8, 2016 The webinar is designed for potential participants who want to learn more about what to do, how it should be done. It will feature conservator experts in these kinds of restorations.
We will be publishing a sign up for that webinar next week.