Having slivered 100's of optics at Tinsley back in the day. I was the one who suggested using chalk for
cleaning to Oregon group last year. It was used successfully with no issues and provided wonderful sliver
coatings. It was part of the process that I use and others and wrote about over the years for cleaning optics.
This method used for decades before me. In 1824, it was used by John Fraunhofer on lenses before
assembly. It is also used by silverers. Cleanliness is the key to get a clear and bright coating, chalk just works.
II also suggested the use of "Green River" to remove the silver verses FC. Green River has been successfully on the
200 inch and 120 inch mirrors, as well as many optical coating companies and is easy to use.
I think that it is wonderful that the Oregon group has provided this to world. It took the effort of many people who
have skill and willingness to look into cost saving option to ATMer's. I hope this becomes a successful project in
the years ahead.