Around 10 years ago I purchased a 'working' A4000.
So I decided to give it a good clean - there was quite a bit of corrosion on the motherboard (battery was already gone) so I put the board in the dishwasher.
It never worked again!
So I gutted the 4000 and sold all the components but I did throw the case away (just the metal chassis).
So my advice: be very wary about motherboards and dishwasher (especially fragile AGA boards - I think an early 500/2000 board could withstand this type of cleaning but just stick to manual methods for best results
)