Bring a large pot of lightly salted water to a boil. Add macaroni, and cook until tender, about 8 minutes. Rinse under cold water and drain. In a large bowl, stir together the carrots, red onion, green pepper, red pepper and celery. Mix the mayonnaise, condensed milk, sugar, vinegar, salt and paper. Add the macaroni, toss gently, cover and refrigerate for at least 8 hours. I usually make this a day ahead of time, and stir it occasionally to blend the favors. The macaroni will absorb some of the liquid.