Slowly brown the beef bones in the margarine in a large saucepan over medium heat for 30 minutes, stirring occasionally. It doesn`t brown the chicken bones.
Add the water and the rest of the ingredients. With the pot open, simmer gently for 3 to 4 hours, repeatedly skimming off the foam that forms on the surface.
Remove the bones and vegetables and pour the stock through a sieve. Put in a cool place and scoop the fat off the surface beforehand.
Both stocks develop the best taste when left to rest for 24 hours. Then use as needed.