Putting the jars in the refrigerator for 24 hours to defrost is the easiest method but takes pre-planning. If you need something thawed right away, set a jar in a pot of water and bring it to a gentle boil, then a soft simmer. If you get the outside ½ inch thawed, you can also slide the contents into a pot and heat five extra minutes to thaw out the puree. Be sure to test before giving to baby.
You can also use a microwave to heat fresh or defrosted food. Simply place the open jar in the microwave for 20 seconds. Stir and microwave again for 20 seconds. Repeat until desirably heated. Be sure to test before giving to baby.
To keep food pure, you should not feed your baby from the jar and then re-store. For smaller serving sizes transfer the desired quantity to a feeding bowl and return the remaining to the refrigerator. Keep in mind the freeze by date on the label.
It can still happen that a jar breaks. Do NOT consume any foods from a cracked jar.
Happy feeding!