Meopta’s Anaret is a Tessar formula lens. So, the rear elements were soldered together and after cleaning, while you tried to mount them, they got separated. Now you have 8 reflection surfaces instead of 7, which is not a big loss. The real problem is to avoid scratching the two previously soldered elements, while tightening them together. And you can avoid this by using a liquid, which won’t dry, so won’t leave marks. I suggest you a very fine oil (like the one used in nailing machines or mechanical clocks), but put very few of it and only on one element. Would you have an optical distortion from this oil layer? I don’t think so, as the layer will have parallel surfaces (where the optical elements were soldered, the curvature is the same). On the contrary, things might even improve, as this layer will also play the role of an antireflection coating.
Although, the Anaret is a cheap lens, good only in 50mm (the 80mm is crap) and only for small contrasty enlargements (less than 6x). I suggest you to replace it with a better, 6 elements lens, and use the Anaret as a magnifier (enlarging lenses are not only the best magnifiers you can find, but also the cheapest ones). For a paperweight, the Anaret is to light.
Paper weight?
