Absolutely! Microfiber cleaning cloths are with me wherever I go, be it around the house, or to the office at work. I use them for cleaning laptop and computer screens, flat screen TVs, iPads, smartphones, and all of our eyeglasses. And when I say I have them with me everywhere, I mean just that. I have a minimum of two in my purse, a stack of them in my lunch/tote bag that I take to work (in case anyone I work with would like to have one or try one), two at my desk in my home "office", one on the kitchen counter near where my husband keeps his reading glasses, and one on the end table in the living room where I usually sit to read on my Kindle or iPad2.
However, that said, I agree somewhat with OldRoses' comment. In a perfect world, you could get the cloth wet and wipe your mirrors and they would sparkle and shine like new and be crystal clear. Not! Nor would I use them on windows, unless I was out of glass cleaner. Don't get me wrong, if they are brand new, you can get a "nearly streak free" clean. But once they have touched oil or grease and been washed, do not use them on windows and mirrors.