So I recently got a LOMO R-15 (ЛОМО Р-15) microscope, that badly needs some cleaning and servicing. So let’s start with the XY stage which is a LOMO ST-12.
As can be seen from this image it is slightly rusty and really dirty.
I basically started by disassembling it and cleaning all parts in the process. There was quite a lot of excess grease and oil on it implying that someone had a go with this before.
About the scales: The scales are just printed so care needs to be taken in order not to dissolve the paint.
In my case I couldn’t fully get the rust/oxidation off the slide holders, I didn’t wanted to grind the coating off the metal so I just let the small spots alone. Upon reassembly I added small traces of oil to the sliding/moving parts.

So after this cleanup my ST-12 does no longer look as awful as it was.