We clean our share of dirty glass in the Conservation Lab at The Corning Museum of Glass, but occasionally we get some unusual requests. Recently, one of our colleagues brought us objects from his personal glass collection that withstood a house fire. Soot on glass artwork and food stains on bakeware may not be the most natural connection to make; however, our conservator instincts recognized that in both cases organic materials had been heated to high temperatures, so we started by revisiting an old blog about cleaning Pyrex.
To tackle this new problem, we wondered if we could use lower concentrations of sodium hydroxide if we soaked the objects for a short period. The surface of each object and the smoke deposits varied, so we needed to work flexibly– what worked for one object did not necessarily work for all. For example, we used a higher concentration of sodium hydroxide to loosen soot on some objects with sensitive surfaces so that we could soak for a shorter time and avoid vigorous brushing.
We worked object by object, gradually increasing soaking time and/or concentration of sodium hydroxide until we could remove the soot by swabbing or brushing gently. The general idea behind our process is: soak, test, assess, then adjust and repeat as necessary.Read more →