Scrub lemons and dry well. Cut each lemon into 8 wedges and each wedge in half.
Place lemons in a bowl with the salt and mix well.
Put lemons in a glass jar with a non metal lid. Add juice to cover, add olive oil if using. Leave at room temperature for 5 days shaking the jar from time to time to mix the juice. After 5 days store in the refriderator.