Fill your crockpot with your bones, meat bits and skin
Fill the crockpot with water until the bones are fully covered – making sure to leave at least 2 inches of the room at the top
Add salt (optional)
Plug in your slow cooker and set to low. This works best with slow cookers that won’t automatically turn off after a certain amount of time. If your slow cooker can only be set to a maximum of eight hours, time this out so that you can reset it before you go to bed as well as when you wake up again the next morning.
Let your broth simmer on low for up to 24 hours.
Once 24 hours have passed, unplug your crockpot and let it cool 30 to 60 minutes.
Cover a large bowl with a large strainer and carefully, using oven mitts, pour the broth and bones over the strainer into the bowl.
Once all the broth has dripped through, you can throw out your bones. You can also save your bones if you want to make a second batch with them.
Get out roughly 4 small Mason jars (this will depend on the size of your crock pot and how much broth it will produce). Using a Mason jar funnel (often used for canning), pour your strained bone broth into each Mason jar, leaving at least 2 inches or so of room at the top. This is so that if/when you freeze your bone broth, the Mason jars will not crack as the broth expands while freezing.
Leave your Mason jars on the counter until they are fully at room temperature. Screw on Mason jar lids but don’t fully seal them. This will allow the broth to breath so that when you freeze them, the jars won’t crack as the liquid expands.
Once your broth has frozen completely, you can seal the lids on the rest of the way.
You may also choose to keep your phone broth in the fridge, but if so I would suggest using it up within one week.