About 6 months ago I used, as an experiment, a common chemical sold as "Break Cleaner"* on a set of Steinway flanges for cleaning verdigris. I removed the pinning and vigorously sprayed the flanges using the tube supplied with the can -- about 3 cans for 88 flanges. These flanges are still in good condition. Has anybody used this product with long term success?
* Sold at auto supply companies as break cleaner. The ingredients listed are: Methyl Chloroform 71-55--6, Tetrachloroethylene127-18-4
I believe this is commonly known as carbon tetrachloride.