Answered By: Regan Brumagen
Last Updated: Dec 01, 2016     Views: 10

Thank you for contacting us. I have contacted our Conservation Department here at the Museum and wanted to pass along their answer: 

"For cleaning glass we generally recommend washing with a mild detergent (something with no dyes or scents) and warm water. Followed by rinsing in de-ionized or distilled water to rinse off any minerals that are found in tap water. I think in this case it might be helpful to use a brush, cotton swab, or even a bamboo skewer to mechanically remove some of the material in the bore holes. I’m not sure about any chemicals that would specifically remove the brass and iron oxides. [The conservator] suggests poultices (basically cotton balls) soaked in 20% formic acid for the copper (brass) staining/deposits and soaked in 10% oxalic acid for the iron staining/deposits. They should be left on for about 10 to 20 minutes and rinsed well with de-ionized or distilled water (or it could be done before washing them as I described yesterday). Neither of these should affect the glass or any wires that may still be attached (the wires may end up a little shinier because some of the surface corrosion will be removed)."


We used orange juice. The oxides in all those
thousands of holes were COMLPETELY dissolved and
washed away with tap water. This approach took only
6 hours to turn something on the order of #2 gravel into
brilliant, clear ice. ALL surface residue was also released.
Most sincere thanks for your kind attention. Please pass
on the nutritious solution to your conservators.