There is some pretty decent information at this site on the subject. http://www.ptg.org/cgi-bin/webglimpse/usr/local/clients/ptg/home/public_html/arc hive/pianotech?query=Whitening+Ivory&lines=on&errors=0&age=&maxfiles=50&maxlines =30&maxchars=10000&cache=yes Keith McGavern Registered Piano Technician Oklahoma Chapter 731 Piano Technicians Guild USA
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