I found this video. Very interesting: _uceJ0pICT4
And as an addition, part of another article:
When folks prepare leeks for market, they typically trim off much of the long, floppy, green upper leaves (“flags”) as they just wilt and are unattractive. However they’re not altogether useless despite their fibrousness. They may be too tough for a vegetable, but I chop those parts and dehydrate them on a screen rack (preferably nylon) hung over the cook stove. When they are brittle-dry, I run them through my Corona grain mill (adjusted so that they don’t gum up the plates) and out comes a brilliant jade-green powder. I may use this in soup stocks but mostly I steep this in a bottle of vegetable oil along with crushed and sifted dried celery leaf (the dark part you throw away), homemade garlic powder and paprika, and maybe some kelp powder.
