Weeding in libraries is often like the gardening chore it is named for: sweaty hours spent among dirty tangles to clear out messy undergrowth and remove unwanted materials. But the analogy stops there - the intellectual pursuit of a well-managed collection includes much more than identifying and removing materials from the shelf. In fact, the daunting, many-faceted weeding process can keep librarians from tackling this very crucial task. A collection left unassessed, left to grow ungainly, is also a missed opportunity to add value, and real cost savings, to the collection through weeding. Santa Clara University Library undertook a reference weeding project in 2013/14; library staff reviewed and relocated over 7,800 titles. Goals were to make the reference collection more relevant to current research needs and to redesign the library's first floor to create more high-demand user space. The project involved multiple library units with multiple workflows, with staff including librarians, paraprofessionals, and student workers. This poster presents detailed data on the cost of weeding a book in a mid-sized academic library, based on staff-time estimated during this project and national wage averages. These data, when compared to the “Cost of Keeping a Book” (by Courant and Nielsen, 2010), demonstrate the value associated with weeding and how, by acknowledging the cost associated with keeping a book, libraries can make evidenced-based decisions that may incentivize the weeding process and perhaps even lead to a more cost effective migration to building ebook collections.