The following useful information was sent to us by Farm Share member Gerry Chamberlin. Thank you Gerry!
As I was cleaning the leeks it occurred to me that maybe some in the CSA aren't familiar with how to easily wash them. When I took a French cooking class some years ago, we were told how to make the cleaning easy (I don't know that this a "French method", just that this was how we were instructed on easy cleaning).
Cut off the dark green because most recipes use the white/light green portion. Cut off most of the roots but not so far back that the leaves come apart.
Make two vertical cuts from the dark end to 1/2" or so above the root end.
In other words, make one vertical cut and then, perpendicular to it (90 degrees) make another vertical cut so the leek remains held together at the root end.
Rinse by fanning out the 'leaves'; tap a little to shake off extra water.
Hold the leek sections back together on the cutting board and, starting at the dark end, cut your desired pieces crosswise working toward the root end.
The advantage of doing it this way is that the root end holds it together when cutting down the length of the leek.
Here is a 2.5 minute video by Gourmet Magazine that gives two cleaning options. (I noted this chef only does one vertical cut in the second version shown.)