My mechanical keyboard has started to generate repeated characters when some keys are pressed. Here I show how to easily clean the switches (cherries) without dismounting them, so that the keyboard will work correctly.
Initially, 22 keys failed. After a quick cleaning, all key work right again.
UPDATE:
With time, some keys have started to fail again. More cleaning solves the problem for some time, but at the end I had to get rid of the keyboard. I think switches are of a bad quality.