Place the zucchini into one gallon water in a large bowl. Stir in the pickling lime, and let stand for 24 hours. Drain and rinse the zucchini a few times, then cover with a fresh gallon water. Let stand for 3 hours, then drain.
Heat the vinegar, sugar, pickling spice, and salt in a large pot over medium heat until the sugar dissolves. Stir in the drained zucchini. Cover and rest the zucchini for 24 hours. Bring the zucchini mixture to a simmer over medium heat for 35 minutes. Allow to cool.
Sterilize about 10 pint-sized jars and lids in boiling water for at least 5 minutes. Divide and pack the zucchini mixture evenly into the hot, sterilized jars, filling the jars to within 1/4 inch of the top. Run a knife or a thin spatula around the insides of the jars after they have been filled to remove any air bubbles. Wipe the rims of the jars with a moist paper towel to remove any food residue. Top with lids, and screw on rings. Store in the refrigerator.