Step 7   Clean the plates with metho on a toothbrush then a rag once that dries steel a Scotch / Jex pad thingy from the Kitchen
              i usually cut these into finger wide strips so i can see whats going on while im using them but you can use the whole thing if you really want. Then gently rub all of the Brass buttons or copper PCBS untill they are nice and bright \ shiny

The first photo shows how the unit started
The second photo shows half the plate cleaned and the other as it was found (this step is not needed only done to compare)
The third is how it should look