It's a pain in the ass - mainly becuase you don't get that many, but you can make "chips" out of spinach leaves with oil and salt (and garlic if you want) on a cookie sheet. We've done it with spinach that was starting to go (like no way would you eat it raw and "wilted" seemed iffy, but cooked to death would be fine). I mean, they're a vehicle for salt, but they were really good.