You know that sheet of paper that comes with your new device that we usually ignore and throw in the garbage? Often there are directions on how to clean it without damaging it. While water is usually safe, you have to be careful that it doesn’t get into the case and fry your electronics. Rubbing alcohol is often used but can cloud and/or damage screens. So what are you supposed to do if you threw out those directions?
This Lifehacker article by Whitson Gordon might help: “How to Properly Clean All Your Gadgets Without Ruining Them”
The other way is to do an online search for the manual. A lot of manufactures have copies of the manuals on their support website.