1) Clean shrimp 
To remove the blackish-gray vein from the back of a shrimp. The vein can be removed with a special utensil called a deveiner or with the tip of a sharp knife. Small and medium shrimp are deveined purely for aesthetic purposes only. However, because the veins in large shrimp contain grit, they should always be removed.
verb remove the dark dorsal vein of (a shrimp)
to remove the dark dorsal vein of (a shrimp).