I used to recover electronics from saltwater and freshwater intrusion, as well as from toilet water, various chemicals both solid and liquid, mould and others for a living. Remove the device from its housing to the degree you find possible and soak it in 99% isopropyl alcohol (NOT rubbing alcohol, which is typically only 70% isopropyl - you want 99% pure). Swirl it around after a couple/few hours, repeat until it appears clean. Remove from the alcohol and allow to dry thoroughly - you can also use a brush to displace any crud during or after the soak. Give it at least a day or two to dry, then reassemble and test. CRITICAL NOTES: 1. 99% isopropyl alcohol is beyond flammable, it's explosive! No smoking, open flame, or anything capable of causing ignition in the room you use. 2. That alcohol evaporates extremely quickly at room temperature - ventilate the room well if you wish to live. 3. Any visible rust or corrosion evident after the above is an indicator that the device will likely not survive, or at least survive for long. Best action in that case is do NOT apply power, buy a new one.