Most modern brakes have curved washers that allow you to change the angle of the brake pads. Loosen each pad, put 1-2 business cards under the rear edge and tighten the pad down, making sure it's aligned well with the rim. The resulting "toe-in" may well cure the squeak. Lack of toe-in is one of the most common causes of brake noise. Probably not an issue with a newer bike but it's also important to make sure the pivot is not loose, allowing the arms to flex forward and back. I w ould use any kind of abrasive as a last resort, particularly on the rims. It's not wise to do something just because you've "heard of it."

p.s. with older bikes one has to physically bend the lower part of the brake arm where the pad attaches in order to toe-in the pads.