Unsubstantiated refutations
Any given troll will likely be met with actual argument based on actual facts, which are substantiated and objective. The troll is then backed in to a corner where the lies or misinformation he has been telling just doesn't work anymore. The troll might then be inclined to "counter" the substantiated facts with a retort and declare victory. Only thing is that the refutation lacks any kind of actual substantiated facts, just lots of hand-waving and obfuscation.