According to Bert at the beginning of "Let's Sing a Song That Everybody Knows", paperclips are very valuable, and are not something to play with on a moving bus. In Bert and the Broken Teapot, Bert considers selling his paper clips in order to pay for David's broken teapot. In Christmas Eve on Sesame Street, Bert goes as far as trading his paper clips for a present to buy Ernie. However, he eventually got them back, and keeps them in a cigar box that Ernie got Bert for Christmas.