1974 Brain Box saves the day.

I had another one Rocket sold me that looked they same way , I guess the earlier models that didn't have that process perfected like the later models which have a black rubbery substance in them !!!!
I can just put clear silicone in there and should be fine just dump that stuff out I will address it before storing im sure it still functions properly .

Be careful using silicone. It has a very high coefficient of thermal expansion, so when the temp changes a lot, it can tear parts off the circuit board