I read in INSTRUCTIONS FOR REPAIRING PRONTOR-PHOTOGRAPHIC SHUTTERS at sheet(/page) No. 14: "Remove shutter blades from shutter, place blades on PLANE surface and wipe with a DRY cloth. Be sure to avoid fingerprints on shutter blades, as perspiration will destroy protective finish and thus give rise to rust formation." "wipe with a DRY cloth.." and "protective finish" makes me a little worried. Any comments, anyone?