Place oven rack in the lowest position
Preheat oven to 375°
Wash blueberries, drain, and place them in bowl
In separate bowl, mix together sugar, cinnamon, salt, and cornstarch
Sprinkle over blueberries
Place one pie crust in pie dish
Dock pie crust
Pour berry filling into crust
Dot butter over filling
Unroll or unfold second pie crust, and cut into 1/2 inch strips
Weave strips into a lattice over top of filling
Crimp edges
Bake approximately 50 minutes or until crust is golden brown and filling is bubbling