Crossword clues for the word: BOXTOP The word BOXTOP has appeared as an answer to at least 5 crossword clues on different crossword puzzles. Crossword clues for BOXTOP Showing 1 to 5 of 5 results Clue(s) Cereal buyer's proof of purchase Old-fashioned proof of purchase Old-timey proof of purchase Proof of purchase for some contests Proof of purchasing cereal