Washing is too aggressive for delicate blackberries, so don't rinse them until immediately before eating or using them or they may turn mushy. Rather than rinsing them under running water, a quick, gentle dip allows you to clean your blackberries while maintaining their shape. A quick chill in the refrigerator beforehand helps blackberries stay firm during washing.
Chill your blackberries.
Put the blackberries in the refrigerator for at least an hour before washing them.
Dip, but don’t soak.
Pour the blackberries into a colander or fine mesh strainer. Fill a bowl larger than the colander or strainer with cool water. Dip the colander or strainer into the bowl of water, and gently swish the berries around in the water for a few seconds. Remove the colander or strainer from the water, and jiggle lightly to drain excess water.
Let the berries dry.
Line a baking sheet with paper towels, and spread the blackberries in a single layer to dry.
Hulling
It isn’t necessary to hull blackberries, but if you don’t like the added crunch that the hull provides it can easily be removed. Simply insert the pointed tip of a knife or a vegetable peeler into the opening of an individual blackberry, being careful not to go too deep and penetrate the exterior. Rotate the sharp tip around the inside of the berry until you’ve made a complete rotation. Angle the sharp tip to scoop out the hull. Repeat with each blackberry until all of the hulls have been removed.