Measure pears into a large pot. Add vinegar, raisins, onions, ginger, spices and salt. Measure sugars together and set aside. Mix certo crystals into fruit mixture. Place over high heat and stir until mixture comes to a full rolling boil, add sugars and boil hard for 5 mins. Stirring constantly. Remove from heat and skim with a metal spoon. Pour into sterilized jars and seal. Place jars in a boiling water bath and process for 10 mins. Remove jars from water and cool. Store any jars that don't seal in the refrigerator. Makes 5 cups.
