Clean herbs as you would clean lettuce leaves: swish them around in a large bowl of cool water to remove dirt and dust from the leaves, lift them out of the water, shake off any excess water, dry them in a salad spinner or pat them dry with paper towels, roll them up in clean and dry paper towels, and store them thus wrapped in a plastic bag in the fridge. Herbs treated this way will keep very well for at least a week.