You can Poison Steel types, and you can't Burn Fire types. This assures you the fact that everything will be taking damage, since Dusclops' Atk/SpAtk are pitiful (even with Calm Mind for the SpAtk).
DynamicPunch hits Steels SE, and then you can burn them. Fire- Types are Frail,(Name me a plausible OU Fire-Type that's defensive, besides Heatran, who gets downed by DynamicPunch) so you could just keep DynamicPunching them until they die / Confusion kills them.