To ensure you get the most juice out of a lemon, you need to make sure your lemon is as soft and malleable as possible. There are a couple different ways to soften a lemon before slicing: (1) ROLL the whole lemon on a hard surface to loosen its membranes [this is our preferred method]; (2) SOAK it in a bowl of warm water for 10-20 minutes; or (3) HEAT a whole lemon in the microwave for 20 seconds. According to Kelli Foster at Kitchn, microwaving lemons for 20 seconds does give you more juice than lemons microwaved for just 10 seconds or lemons pulled straight from the fridge.