They were once advertised with the slogan “Polly wants a cracker?”

The answer to the crossword question “They were once advertised with the slogan ‘Polly wants a cracker?’” is SALTINES. This refers to a popular brand of crackers that was advertised with the slogan “Polly wants a cracker?” in the early 1900s. The slogan was accompanied by an image of a colorful parrot, which became a recognizable symbol of the Saltines brand. Saltines are a type of thin, crispy cracker that are typically made from flour, salt, and water. They are often used as a snack or served with soup or chili. Overall, Saltines have become an iconic part of American culture, and their memorable advertising campaign has helped to solidify their place in history.