Put the leftover bones and skin, from a chicken carcass, into a large stock pot.
Add vegetables like celery, onion, carrots and parsley; cover with water.
Add salt and pepper; about a tsp. salt and 1/4 tsp. of pepper, or to taste.
Add garlic powder and liquid smoke, if using.
Bring to a boil and immediately reduce heat to bring the stock to barely a simmer.
Simmer, partially covered, at least 4 hours, occasionally skimming off any foam that comes to the surface.
If making stock for future use in soup, you may want to reduce the stock by simmering an hour or two longer to make it more concentrated and easier to store.
Remove the bones and vegetables, with a slotted spoon or spider ladle, and strain the stock through a fine mesh sieve.
Remove from stovetop and allow to cool; place in an airtight container and store in refrigerator.
