Step 1
Place the cooked chicken carcass in a large pot, then add a handful of raw vegetables such as carrot chunks and tops, celery chunks, onion pieces with skin on, fresh thyme or rosemary sprigs, a bay leaf, and black peppercorns.

Step 2
Pour in enough cold water to cover completely. You will probably need around 10 cups (2.8 liters). 

Step 3
Bring to a boil, reduce to a gentle simmer, and cook with the lid half-on for about 1 hour, skimming off any fat that rises to the top of the pan, if necessary. 

Step 4
Remove the carcass and discard, then pour the liquid through a sieve into a large storage container.