702.2. Buffs can be added or spent.
702.2.a. To Buff a Unit , a player chooses a Unit and then places a buff on it. That Unit is Buffed for as long as the buff remains on it.
702.2.b. Spending a Buff removes a single Buff counter from a Unit .
702.2.b.1. A buff cannot be spent from a Unit that does not have a buff.
702.2.b.2. A player can only spend buffs on units they control.