Speckles inside CRT tube

I have two Minibee terminals. One is working fine, but the other has weird speckles on the inside of the tube. I turned up the brightness so that the speckles are visible in the photos below. The spots are black, and are behind the glass but a few millimeter in front of the phosphor layer. It seems as if the tube is covered by outer layer of glass; the speckles are between the tube itself and this outer layer.
Is there anything that could remove the spots?
If not, how difficult would it be to find a suitable 12" replacement tube?

This phenomenon is called "CRT cataracts", I believe. That search term will lead you to a lot of resources.

Ah, thanks! I learned something today. This will be a nice project to repair.