1. Soak sweetbreads in cold water for at least four hours, or up to overnight, changing the water three to four times.
2. Place sweetbreads in a medium pot, cover with cold water, and add lemon juice and a teaspoon of salt. Bring to a boil and cook for five minutes. Remove sweetbreads immediately and place in an ice bath.
3. Once cool, place sweetbreads on a few paper towels and dry very well. Remove all the membranes and veins. Place in refrigerator overnight.