To begin, prepare your jars and canner. Jars should be washed, inspected and ready for use.
Combine the shredded/thinly sliced cabbage in a large bowl with the canning salt. Toss the cabbage to mix the salt all through it. Cover the bowl with a tea towel and set it aside for 2 - 4 hours.
Place cabbage in a colander, and rinse with cold water to remove as much of the salt as possible. Work in batches, and then let the cabbage rest in the colander a few minutes while you prepare the brine.
Combine the water, vinegar and sugar in a large, nonreactive pot. Bring the mixture to a boil, and let it boil for 1 minute. Reduce the heat to keep the brine nice and hot while you do the next step.
Put the shredded cabbage in a large bowl and add the shredded carrots. Mix them together.
Pack the cabbage and carrot mixture into your jars, leaving 1/2 inch of head space.
To each jar add a pinch of celery seed and 1/8 teaspoon of pickle crisp.
Ladle in the brine.
Remove any air bubbles with a bubble wand, and adjust the volume to maintain the head space if needed.
Wipe the rims of the jars with a damp cloth that is dipped in white vinegar to remove any residue.
Close the jars with a lid and ring.
Process the coleslaw in your canner for 15 minutes. (Remember to always adjust for your elevation. Check the chart I have mentioned in the article above.)
Allow the jars to rest on a lined surface in a draft-free location for 12-24 hours.
Remove the rings, and test the seals. Label the jars and store them in your pantry.
Allow the jars to sit in your pantry for 4 weeks, giving the cabbage time to pickle and for the flavor to develop.