<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF"> What we have here is a case of old fashion ion oxidation.  Many cheep pianos from the 60's and 70's, (particularly 70's), used cadium plated screws.  Many other parts, however, were still nickel plated, (i.e. pressure bar).  Thus the nickel metal and the cadium metal chemically react with each other, (like NiCad batteries),  and you get a dull greenish-yellow oxidation.  I have seen this on a lot of cheep spinets too where they used cadium screws to hold nickel plated brackets in place on the keys which hold the stickers.   Rob Goodale, PRT Las Vegas, NV   Doug Garman wrote: <blockquote TYPE=CITE><style></style> From time to time I open an upright and find the pressure bar and screws coated with a light yellow-green powder.  What is this?  Oxidation?  How should I clean this off, or should I?  Saw one yesterday on a Wurlitzer spinet (2-pedal). Thanks --- Doug Garman  :o)  </blockquote> </body> </html>