Wash; drain; and shell peas.
Boil small peas (less than 1/4") 3 minutes, larger ones (1/4 to 1/3") 5 minutes.
Drain; rinse in hot water; drain.
Pack hot into hot jars, leaving 1 -inch head space.
Add a sprig of mint to each jar.
Add 1/2 teaspoon salt to each jar, if desired.
Cover with boiling water, leaving 1-inch head space.
Remove air bubbles.
Process 40 minutes at 10 pounds pressure.
If peas are large, process 10 minutes longer.