How much extra to pay someone who helped recover my full deposit?

[WWGD]

I hired someone to help me clean up the apartment from which I recently moved out. He did a good job working with me and I received my full deposit back; he had more training in full cleaning than I did and led the way much of the time. I feel I should give him some extra money for his help in getting a full refund. How much should I give him, and what should the amount I give depend on?

 

[Greg Bernhardt]

Tips for me are all about going the extra mile. It appear this person did so it's nice to offer. I would think about an extra $10 per hour.

 

[Astronuc]

One could give half of the deposit, or half of the difference between the full deposit and whatever one would have received without the help.