You can use a brush to remove hard dirt and to clean it thoroughly. Produce like cauliflower, broccoli, or lettuce should be soaked in cold water for at least 1-2 minutes. Some produce, such as raspberries, should not be soaked in water. To wash greens, separate the leafs and soak them in a bowl of cold water for a few minutes. Do not wash the produce with soap or detergents. For produce with thick skin, use a vegetable brush to help wash away microbes. After washing the produce, dry with a clean paper towel, this can remove also more bacteria.