Remotely modern remote control PCBs are manufactured using water soluble flux. They are put through a rinse but barely, residue remains behind.
When you get them wet, that residue forms acidic pools that eat at the metal and create conductive traces, which are usually most problematic on close pitch IC pins, but less so on something using very low voltage.
Long story short, don't let water bead up on these and dry to create increasing strength pools of acid. Examine, rinse, use a rinse agent or alcohol mix to promote sheeting action by lowering surface tension, and shake excess off. That is your best chance for survival after an event. That old wisdom to "throw it in a container of rice/desiccant" to dry it out, is only combating the wet-issue, not the corrosion issue, so isn't much more effective than just pointing a fan at the widget unless you have a horribly humid environment.
You don't need any special cleaner to get water based flux off, unlike the old rosin core flux that is seldom used now except on components that were hand soldered. That will come off with alcohol. No-clean flux if it's a hard clear blob still, can stay there and is fine.