Holy shit 
Exactly
This afternoon, I had some time to do a quick cleaning. Glass cleaner and papertowels for the outside, and vacuum cleaner for the inside.
Sadly, the PCB is missing

but I found 56 german D-Mark inside

( ok, pretty worthless now ). The power supply, audio board and a G07 with burn in was also inside.
While cleaning the outside, I told to myself, this isnt what it looks like, its some.... dirt from the ground, choclate pudding or something else . Finally, it did not smell.
The edge near the control panel has been eaten from the goats, the whole T-Molding is missing there. The control panel was stuck because of rust but some heavy duty multi oil works wonder. Anyway, I must have a closer look when it got sandblasted because rust took already some of the metal away.
Ok, whats on the list now:
- PCB needed
- Trackball refurbish ( its stuck )
- Sideart and most graphic overlays needs to be changed to new one
- power supply, audio and monitor needs testing and refurbishing ( rust, dirt... )
- coin doors and control panel needs sandblasting and new coat ( coat, not goat

)