oh man, thats bad.
Infact its one of the worst Ive seen in a long time.
I would say there is a million to 1 chance of it ever working again
But sure, put it under a tap of water, wash of all the crud, and have another look
only when you get the board clean will you see the damage to the outer traces. There are components missing, and many reduced to rust. The traces are long gone underneath.