Cut a thick slice from the top of each apple, and set them aside in cold water. Remove the cores. Using a melon baller, scoop out the pulp, leaving the skin intact and as thin as possible. Chop up the pulp( not to fine) and mix with the celery, salt, raisins and enough mayonnaise to moisten. Fill the apple cups with the mixture. Drain the tops well, dry on paper towels and place one on each apple cup. Serve on a bed of lettuce. Makes 5 servings