1) Drain beets and reserve 1 1/4 cups liquid.
2) Keep beets in 1 1/2 to 2-quart jar.
3) In a medium saucepan mix vinegar, sugar, salt, cloves, peppercorns, bay leaf and reserved liquid.
4) Boil the mixture, decrease heat, and simmer for 5 minutes.
5) Mix onion slices to jar.
6) Stir beet liquid over beets and onions.
7) Cover and chill for several hours or overnight.