Stand the sweetbreads in cold water for 20 minutes, wash, and drain.
Put sweetbreads in a cooking pot with 2 quarts if water. Add 2 tablespoons of vinegar and 1 tablespoon of salt. Mix and bring to a boil.
Simmer for 30 minutes and drain.
Cut into pieces and mix an equal amount by weight of crumbled dry stale bread or dry dog meal with pieces.
Freeze any excess quantities for future use.