With shelter at home, we've been getting weekly farm boxes, some of them came with a lot of leafy greens. Wrapping the lettuces, chard, spinach, basil, mint, etc., in slightly moist paper towels and placing them inside unsealed plastic bags does the trick for us. If you first rinse the greens, shake out as much water as you can and there is no need to moisten the paper towels. That makes the green leafy vegetables keep for a week or even longer. How long obviously depends on how fresh the greens are when you store them.