"This is what he did to our other TV (6month old TV!)"
Keep all the kit and change the child!
Seriously, when my children were young I had top flight hi-fi stuff, B& O TV and they never went near it all because they were taught to keep away from it all - and they did!. It's all about setting boundaries of behaviour.
Having said all that, my daughter has clearly not continued this practice as my 2 year old grandson (remember 2 years old) was given a tablet (electronic type!) at Christmas which he smashed within hours. He has his own Apple iphone on which he plays games. Of course he also has a flat screen TV and DVD player in his bedroom.
I'm clearly an old fossil with my attitudes.
Finally, the Beo4 is a very sturdy unit and I would take it apart and clean and dry it all from the inside out.