I use RadTech soft microfibre cloths or (on the iPhone) the little black cleaning cloth provided with the iPhone. And, yes, as Clay mentions, it's important NOT to spray anything directly ON the computer or monitor! I spray a little into a soft cloth, apply that gently to my MBP or whatever I'm cleaning, then gently wipe it with the RadTech microfibre cloth. I also use RadTech keyboard protectors to protect the monitor on my MBP from being marred by the keys when the machine is closed.