Your best bet is to fully disassemble the machine, let it dry fully, clean any corrosion with rubbing alcohol.
Then you’ll want to replace the keyboard, unfortunately you will have to do a full keyboard replacement, and it will take some time and patients.
[guide|12353]
Start with the above guide, you will then want to continue on and peal back the black backlight, and then will need to remove about 100 tiny screws to swap your keyboard.
This MAY help solve your problem, but no guarantee.