I carry a micro cloth in my pocket all the time. Just part of my routine in the morning...I keep it in my drawer with my wallet. When the wallet goes into my back pocket the micro cloth goes into the right front pocket along with my inhaler.
My personal micro cloth of choice is the Fellowes Perfect Clean (
Default). I use it for keeping my laptop screen and keyboard dust free. I wipe down my BB every once in a while. I also use bluetooth headset so I don't have to wipe it down every time I use it. For some reason the display on my car receiver gets dusty quickly (construction areas probably) and it comes in handy there as well. I clean my glasses and camera with it. When it gets too soiled to clean effectively I just wash it with dish soap or laundry detergent in a sink and let it air dry.
I'm not a clean freak but I've found that if you regularly dust some things (like the laptop screen and keyboard) then you never have to CLEAN them.