Stap 4 vertalen
This is your goal: disassemble the switch parts, wash them thoroughly in clean water, and dry thoroughly.
Optionally, use a silicon grease on the plastic and rubber parts, and a polyphenyl ether (PPE) lubricant on the gold contacts. If you don't have a PPE lubricant a very very light coating of a light lubricating oil also works. This step is optional.