I take 2 large onions and cut them into large chunks. Then I'll take about 6-7 garlic cloves and peel them. Throw all that into a large stock pot. Add your frozen chicken "leftovers"
Do it this way...
"leftovers" from one chicken .........chicken, onion and garlic in water
Once it comes to a rapid boil, there will be a brownish foam on the top. You want to skim this off. I don't know what it is or why it forms, all I know is Gramma always skimmed it off so I do too. Once you have done that, turn it down to a slow simmer, cover and let it cook, covered for 24 hours adding water when necessary.
When it's done cooking, pour through a strainer into another pot. Make sure there are no chicken parts, onions etc. left in the stock.
After it cools a bit, put your pot into the refrigerator so the stock can cool and the fat can come to the top and solidify for easy removal.
Heat your stock back up, then ladle into your hot, sterile jars and process for 15 min. at 10 lbs pressure.
I ended up getting 9 pints that I processed and one quart that I put in the fridge to use on Wednesday for soup and sandwich night.