Make sure all containers, work surfaces, your knife, and your hands are thoroughly cleaned and free of any dirt, grease, or grime.
Let them air dry completely for 12 hours. If you have loose stalks and leaves like I did, you can bundle them together with kitchen string or rubber bands, and hang them on a line of clean twine to dry.
Once all the leaves are dried (free of surface water, not dehydrated) and slightly wilted, chop them to your desired size—I did small slivers. You can also cut them into larger chunks or leave them whole.
In a large bowl, sprinkle salt onto every layer of greens. Knead the vegetables with clean hands to work the salt in, until they are well coated. Transfer everything to a clean container with a cover. Marinate in the refrigerator for at least 3 days. After three days, they are ready to be used!
Use clean utensils to take what you need each time you use these preserved greens, and return quickly to the refrigerator.
Be attentive to any signs of spoilage like weird smells or mold.
These preserved greens are mild, but also relatively salty. Generally, when I cook with them, no additional salt is needed in the dish. Taste as you go when cooking with them.
If you find they are still too salty for your chosen application, you can rinse them before cooking. If you do this, be sure to squeeze out all of the excess water before using.
If handled properly, these greens can last in the refrigerator for several months.