How Do You Discipline When...

How can I discipline Von for dumping his plate on the floor after he is done eating, then piece by piece throw anything else he spilled onto the floor when he thinks he is helping clean up? How can I stop him when he see us put our plates on the floor for the dog and then wipe down the table, so he does what he believes is the same as we are when instead he is throwing his food all over the floor.

Von also loves to help with the sweeping, dusting and vacuuming. He will sit right in my dirt pile and sweep it all over the floor, flinging pieces back where they were.