I must admit to being a little afraid too. My Beolab works as it is, so I haven't opened it yet.
I did open the Beomaster tuner though! Nothing fearful here. I had to do much cleaning, there was a layer of white powder (white rust, or zinc oxide, due to damp storage conditions) all over the silver galvanised steel parts and the trimmers were black. Now my technique is to use Mr Clean for the metal parts, then when the surfaces are clean and shiny, I oil them slightly (Mobil One) and wipe them again.
Oil will also remove the black oxidization on the trimmers quite magically!
The DIN sockets were cleaned too because they started to oxidize. They look as good as new now (just one hour to do that!).
The bottom steel plate will be replaced completely. The real difficulty will be finding the correct paint!
I'll publish the photos when I get the palissander top from Martin. I also bought a new signal meter to replace the really hazy one that came with the tuner.
Could you publish a picture Paul please?