OMG I've never done anything so labour intensive that yields so little obvious rewards!!!! I threw two hours at this and apart from almost entirely separating my index finger from its nail and I'm no longer certain my toothbrush is going to be ok for my teeth any more I've made this much progress, both sides. Obviously did the general bay plastics for a nice easy win with some diluted APC.
Before:
After:
50/50:
Carb cleaner is an absolute must to anyone who recommend it. I tried some engine cleaner/degreaser, and it removed precisely nothing.
However, when you get some of this unknown matter off, and it starts to look shiny, it all becomes worth while. This is going to be a project in itself an hour or two each weekend to work my way around