I got my hands on a Mavic that crashed in the ocean (supposedly lost GPS and went down; only in water 20 seconds). The owner tried drying it out but when it was powered on it stated to smoke. The salt water had corroded components and left too many electrically conductive deposits on the boards. As soon as he got it out of the ocean, he should have immediately flushed it with fresh water (as we divers do with our camera equipment) or an electronic component cleaner to try to save it.
Anyway, here's what it looked like when I took it apart.

Anyway, here's what it looked like when I took it apart.





