Hi Mike, The F2's mirror is often smudged by the damping foam which is deteriorating with age. If this is the case, then the first thing to to is to replace the foam. The smudges on the mirror can be gently removed using a fine lens brush, after giving the mirror a breath of warm air to condense it. I have cleaned the mirror of several F2s in this way without any damage. Happy shooting, Sover
