Add hot water to a little over ½ of the water bath canner and bring to a boil.
Using a canning funnel and a ladle, pour the hot pasta sauce into the sterilized jars, leaving 1 inch of headspace. Remove air bubbles and wipe the jar rim with a clean damp cloth or papertowel. Using the magnet lid lifter tool, grab the jar lid from the small sauce pan, and carefully place it on the jar. Loosely screw the rings onto the lids to ensure the lids stay in place.
Place the jars on the inner wire rack of the water bath canner and lower it into the boiling water. Add the lid to the canner. Process for 40 minutes in boiling water.
After the 40 minutes is up, turn off the heat and carefully remove the canner lid. Grab the metal insert by the handles (with oven mitts) and raise the jars up, carefully hooking the handles onto the edge of the water bath canner. Let the jars sit for 5 minutes.
Lay out a hand towel or a doubled up flour sack towel on a counter surface. This will act as a barrier between the hot jars and cool counter, preventing the counter and keeping the jars from bursting with the drastic temperature change. Using the jar lifter tool, carefully remove the jars from the wire insert and place them on the towel. Allow jars to sit and cool, undisturbed, for 12-24 hours. Test jars for airtight seals. The lids will not “pop” when pushed down on and will not pop off when pulled up on.