RE: WD-40 for cleaning engine?
Forgot your second question.
I've been slacking off in the maintenance department a bit to. Some timne ago I pulled out a car from 'storage' (it hadn't been run for months) where I had done just that. I though I'd screwed up the engine by neglecting it so I broke it down to check it. To my surprize it looked great inside. I used 30% TQ in that one and no harm done. Usually this is not a good idea.