Decades ago I bought a surplus HP 524A tube type frequency counter (with the neon counting columns for displays) that seemed to have about a million tubes and consumed 600 watts from the A.C. line! While bringing it home on a winter day with the roads covered with slushly snow, the tarp covering the counter blew off and I didn’t notice that until the counter was totally soaked with water contaminated with road salt and all sorts of oil and other crud. Traveling at about 60MPH really forced all that water into every nook and cranny of the instrument.
I knew that HP/Tektronix did wash their equipment with water followed by several other steps to complete the cleaning process. I modified their process and actually used a garden hose to spray every part of the unit, then used a lot of alcohol, then blew as much off as I could with a hair dryer on low heat. This was a military unit so the transformers were sealed which greatly helped plus I removed the frequency standard and cleaned that by hand. The only parts that seemed to suffer were some cardboard tubes covering some electrolytics so you couldn’t accidently touch them and get shocked but they had nothing to do with operation. After letting it set next to a heat source for a few days and re-lubing switches, I tried it and it worked and continued working for a few years until I upgraded and got rid of it.
Just last week I cleaned a circuit board that was contaminated by a leaky NiCad battery with water, vinegar, alcohol, and a heat gun on low. If you are careful and after getting a piece of equipment really clean you let it dry properly, you will probably be in good shape. Sometimes you have to totally dismantle items like the rubber button switch pads on a front panel because they can really trap any water that seeps into them, and carefully clean under ICs. If you haven’t cleaned something using this process before, it might be a last gasp effort. If the unit was on when it got soaked or it was turned on without cleaning, a LOT of stuff could short out and the unit may not be repairable. But if it’s already totally dead and you've exhausted all other options, hey, what do you have to lose?