The picture is down the tube, so you can see the spider holding the secondary. To my eye, the spots look like corrosion and not cleanable, but does anyone actually know what they are?
It was stored relatively carefully - not totally sealed but in a house, with the tube covered with a plastic bag. So huge temperature changes are not likely, but it does quite humid here. It was last in action > 10 years ago.
The only other thing I know about the scope is that it was made by Criterion, sometime before the 1980s.