On a cutting board, cut the head of lettuce in half with a sharp knife. 

Separate the leaves "or cups" and place them into the salad spinner bowl. 

Pour 1 cup of white vinegar into the bowl and add enough water to cover the lettuce.  

Use your hands to gently swish the lettuce around and let it soak for 3 minutes. 

Drain the water and rinse the lettuce with cold water. 

Place the lid on the salad spinner and give it a few whirls or until the excess water is drained out of the lettuce. 

Transfer the lettuce to a clean kitchen towel and allow it to air dry. 

Store it in a paper-towel-lined zip bag for up to a week.