Do not mistake me for an expert.

I figure anything thats been soaked or submerged in water already probably will not be further damaged by a water cleanup.

You might have some luck submerging it in a bath of water thats being agitated to loosen crud gently.

Would all depend on how it looks. If it is just to salvage components a stiff brushing might be OK, but to salvage boards you may scrub off traces by brushing.

I never tried much salvage of corroded boards but have lifted components from them that were fine.

In fact, I might just take the pressure washer and blow off the crud from a distance if I just wanted parts. Lots of variables. Most components are more or less sealed so wet not likely fatal.

Good Luck.

TomW