I just bought a SMC-M 50 1.7 that takes great pics. It is in very good condition and I realize that a few internal dust specs probably aren't worth worrying about. I just don't like seeing them in there. Can anyone reccomend someone qualified to disassemble the lens and clean it? I only live a few miles from the Pentax national service center in Denver, but they say they won't work on lenses this old anymore.