I decided to clean it. I broke the rear cover but it was necessary. I recommend you to dissasembly all and put the motherboard under Isopropyl Alcohol (IPA) (not normal alcohol) at least 1 hour. IPA doesn't conduct electricity so no problem. Try to do it as soon as posible. In my case, it works. The main problem was that the power button was contaminated so introducing the motherboard in IPA cleaned the internal parts of the power button. After that no problem until today. The only side effect was that my mic does not work anymore but this was not caused by the IPA. Have luck!!
"Best bet is to probably open it and clean it. Depending on how bad the cover breaks you could use some electrical tape to tape it up after its back on to hide the cracks and prevent them from getting worse @villaherraiz comment above is a great guide to follow to clean the board off.
