Wash beets.
Trim tops to about 3 inches and leave on root ends.
Place cleaned beets in an 8 to 10 quart saucepan, and cover with water.
Cover, and cook beets over medium-high heat til skins slip off easily, about 20 minutes.
Drain and discard water.
Trim off tops and roots, slip skins off.
Slice beets about 1/4 inch thick.
In a 4 to 6 quart saucepan, combine vinegar, sugar, 2 cups water, pickling salt, and spices.
Bring to a boil over medium-high heat.
(Keep brine mixture hot while you fill jars with beets and onions).
Fill each jar with a layer of beets, first, then, a layer of onion slices.
As you add layers, push down gently with a wood spoon.
Pack jars just to bottom of the neck of the jar.
I always set the packed jar in a pan of hot water, (fill hot water to about 1/2 way up the jar, and put a table knife down inside the jar between the beets and the inside surface of the jar.-- This helps to keep the jar from breaking when adding the hot brine).
Slowly, pour brine in jar until beets are covered over about 1/4 to 1/2 inch.
Move table knife gently in an up and down motion, all around the jar to remove any air bubbles.
Clean the rim of the jar and threads with a wet cloth, set hot, sterilized seal cap on top, place ring on, and cinch down firmly-- not too tight, but, firm.
Place filled jars in Boiling Water Canner, hot, gently boiling water to cover jars, place lid on canner, and process for about 30 minutes.