Mother's Rhubarb Relish

From the Green Shutters Cookbook Lunenburg

4 cups	diced rhubarb
4 cups	diced onions
6 cups	brown sugar
2 cups	cider vinegar
1 tsp	ground cinnamon
1/2 tsp	ground cloves
1 tsp	ground allspice
1/2 tsp	pepper
2 tsp	salt

Measure all ingredients into a large pot. Stir to combine.
Simmer over low heat until the mixture is reduced by half and thickened, approximately 2 hours.
Remove from heat and put in sterilized bottles and seal. Serve chilled. Makes 8 cups