Removing graffiti from graffiti

The section of the Berlin Wall that sat in the plaza behind 520 Madison Avenue in New York City for more than twenty years has been undergoing conservation treatment before it is reinstalled in the building’s lobby. This is a major effort as 70% of the surface required some type of attention. What struck me the most in the article about this project published in the April 9, 2015 issue of The New York Times (“A Section of the Berlin Wall Will Again Stand in Manhattan”, by David W. Dunlap) was that part of the conservation treatment was the removal of graffiti added to the wall during its New York sojourn. Is there not some irony in the fact that if this were still a part of the Berlin Wall instead of the expensive work of art it has become, there would have been no cause to remove the new graffiti.