I just don't get all this fancy stuff. I have cleaned thousands of keys squeaky clean without any further work on 99% of them by using a spoonful of powdered laundry detergent (I like Charlie's or 365) in a liter of hot water. 5-20 minutes is plenty of time. Adding half a spoon of Oxi or washing soda probably helps.
Rinse well about 3 times pouring back and forth between a bowl and a colander, and toss out on a T-shirt to dry for a little while.
All that other rigamarole is just a big waste of time, money, and energy.
If you shake the water out of each key and roll them over right-side-up on the T-shirt, the entire affair, including drying, hardly takes half an hour.