Removing soiling from painted outdoor sculpture

Abigail Mack


Along with the need for more durable and long-lasting coatings for painted outdoor sculpture, is the necessity to develop effective cleaning and maintenance methods. This is especially important for matte and semi-gloss surfaces since they are known to be easily disfigured by soiling and stains can be difficult to remove. If the soil has a nanoparticle component (such as Titanium Dioxide in sunblock) the particles become imbedded in the paint film and, these in particular, have proven to be nearly impossible to remove.

In desperation (before the opening of an exhibit) to remove white handprints on a black painted outdoor sculpture the conservators from the Rijksmuseum kindly gave me access to their cleaning cupboard and a variety of detergents, solvents, erasers, chelating agents, plus a steam cleaner were tested. One class of cleaners showed promise—Oxiclean type detergents owing to alternative “scrubbing bubbles” cleaning action. The release of oxygen bubbles in the detergent was able to lift the previously intractable soil. With this good result, colleagues at the Fondation Beyeler in Basel Switzerland replicated the cleaning techniques on previously non-removable dirt.

Tips session will show images of (desperate pre-opening) tests and images of (more systematic) cleaning tests replicated by Friederike Steckling, Conservator at Fondation Beyeler, and Abigail Mack, Mack Art Conservation.

2015 | Miami | Volume 22