Pick over fruit, removing any stems and leaves. Then crush with a potato masher. Measure crushed fruit until you have 4 1/2 cups. Put into large heavy pot. Add lemon juice, then sugar, and mix well. Place over high heat, stirring, and bring to a full rolling boil. Boil hard for 1 minute, stirring constantly. Remove from heat; stir in pectin at once. Skim off foam, stir and skim off foam. Ladle into hot, sterilized jars and seal. If desired, process as recommended (5 minutes) in boiling water bath.