When selecting your mussels, NEVER choose a mussel that is chipped, broken, or damaged in any way.
Also, never choose a mussel that is open.
1. When selecting your mussels, NEVER choose a mussel that is chipped, broken, or damaged in any way. Also, never choose a mussel that is open. The mussels should be tightly closed and stored in a cool area where they can breathe. When you purchase your mussels, make sure to immediately unwrap them at home so they can breathe, otherwise they might die before you cook with them.

2. Just before cooking, soak your mussels in fresh water. Soak them for about 20 minutes. As the mussels breathe, they filter water and expel sand. After about 20 minutes, the mussels will have less salt and sand stored inside of their shells.

3. Most mussels have what is commonly called "The Beard," also known as byssal threads. The beard is comprised of many fibers which emerge from the mussel's shell.
4. To remove the beard, using a dry towel, grasp the beard and give a sharp yank out and toward the hinge end of the mussel. This method will not kill the mussel. If you were to pull the beard out towards the opening end of the mussel you can tear the mussel on the inside of the shell, killing it. Discard the byssal threads.

5. Remove the mussels from the water. Do not pour the mussels and water into a straining device because the sand has sunk to the bottom of the bowl. Pouring the mussels and water into a straining device would cause you to pour the sand back on top of the mussels. Place these mussels into another bowl full of clean cold water.

6. Once the mussels have been soaked, use a firm brush to brush off any additional sand, barnacles, or other oceanic attachments. Rinse the mussels under cool tap water, and set aside. Dry with a towel before cooking.