i've been trying the windowsil method for the past couple of months, and up until about a week ago i'd have sworn it was having no effect whatsoever. but then i checked it and sure enough, there were
very subtle golden highlights starting to appear in the crevices. i turned it right over so as not to affect the coin too much, but i guess it actually does
work.
i've thought about experimenting with little pieces of various hardwoods to see if it's possible to reproduce some of that lovely old 'cabinet toning' that you see on occasion. i'll probably try it with some low-grade silver Washingtons first though.
~
Peter