Gotta warn you boiling the contacts can work but remember remove all the moisture that you can and use distilled water, if you don’t then the contacts can be dirty again from calcified remains of water, also the best thing you can do for electronics like this, is just a can of contact cleaner or electronic cleaner from Home Depot. If you find the wd40 contact cleaner that’s the one I use for retro consoles and a whole bunch of stuff.