Fogproof means the internal surfaces of the binoculars won’t fog. This doesn’t apply to external surfaces. Typically, the binoculars are pumped with an inert gas and sealed to prevent internal fogging. For external fogproofing, you could apply a safe fogproof solution or wipe to the lens surface to remove the fog. Do not rub your lenses with dry clothes or paper towels as you may scratch or damage the optics.