Grease a 3-cup seafood mold. Combine the soup, cream cheese, and softened gelatin in a saucepan and heat until hot and bubbly, about 5 minutes. Stir well to make sure that the gelatin is completely dissolved and that there are no lumps. Add the crabmeat, celery, green onions, lemon juice, Worcestershire sauce, and seasoned salt. Stir gently but thoroughly.
Spoon the mixture into the prepared mold and smooth the top with a spatula or knife. Cover with plastic wrap. Transfer to the refrigerator and chill until firm, about 3 to 6 hours.
When ready to serve, remove the plastic wrap and loosen the edges of the mousse by running a knife around the sides. Invert onto a serving dish. The mousse will slip out in a few minutes.
Serve with crackers.