The only time I ever saw a microwave recommended for this purpose was in the pro audio forum on CompuServe almost 20 years ago. My distinct recollection is that the person who made this suggestion was from Australia. Glenn Meadows moderated the forum, and perhaps he recalls the thread - but the person who endorsed using a microwave oven gave no further explanation.
-- Parker Dinkins MasterDigital Corporation Audio Restoration + CD Mastering http://masterdigital.com