I would skip the cloth and go straight for compressed air.
I've cleaned lots of PCs and electronics and I find compressed air pretty much does everything you need.
The only thing to watch is.....don't get too close to the components (to the point where the pressure could damage them). I stay about 12-18" away depending on the strength of the air.
The reasons i would stay away from the cloth are that you could physically damage something and static is a possibility (although I think static gets blamed more than it should).