Heat pulp to boiling point and boil gently for five minutes, rub through a sieve to remove seeds.
Combine pulp and skins and cook together five minutes longer.
Mix sugar, corn starch, and salt and blend smoothly with some of the grape mixture.
Stir into the rest of the grape mixture and cook until thick, stirring frequently.
Notes
If a family is fond of grapes, triple the number of grapes, cook, and store for several days in the refrigerator.When making a dessert, take a third of the grapes and add the half-cup sugar, two tablespoons corn starch, and a dash of salt, as above.