Leeks float and dirt doesn't

It dawned on me the other day that I didn't explain one simple fact about leeks.  They need special cleaning as the way they grow they trap dirt in-between the layers of leaves.  The best way to clean them I picked up on foodTV, don't ask me from which chef as I don't remember, is to put them in a large bowl of water.  Agitate them lightly with your hand to losen the rings and let the dirt fall down.  After agitating them let them rest for just a few seconds for the dirt to fall to the bottom of the bowl and voila you have clean leeks to saute and use for your dish.

Call this a lesson in cooking 101.