What metaphors are used in American Buffalo by David Mamet?

The play's setting does more than allow Mamet's trio a space in which to scheme their robbery; it allows the playwright to highlight the notion that the characters are living in a world of metaphorical "junk." Throughout the play, Don and Teach give and receive lessons on such topics as honor, capitalism, and friendship topics which are abandoned and left for "junk" when their robbery plan becomes threatened or when they fear they might miss their chance to make some easy money Although they profess to have solid codes of "business" ethics, their desire to succeed pushes them into a world of moral 'junk."