Yes, clean and dry and test before soldering

A fiberglass PCB cleaning brush from your electronics parts store offers the best method to safely clear deposits and contaminants of the board. It is more abrasive than a toothbrush but not as destructive as a screwdriver :-)

Here's one:
Lenline Fiberglass Scratch Brush - CK3.CO.UK

If the nav doesn't work after re-assembly, use a multimeter to try and find any tracks that may have corroded through, then you know what to repair.
Use normal PCB repairing techniques for any corroded tracks.
Pray the corroded tracks are only on the surface layers, not on the intermediate layers of the multilayer board !!