There's a chance the cloth may cause condensation though. If any of the water droplets happen to gain access to the inside of the vent, this could cause short-circuiting. Besides, blocking the vent in any way is dangerous. if the vent gets too hot, there's a chance the plastic outer shell could become distorted, and condensation could, as previously mentioned, damage the motherboard and other components in the form of a short-circuit.
As for OP, i think it's best to just look up some images. That's what the internet is for
