Students rarely use their graded exams to study. An alternative method of grading exams, based on self-reflection, encourages students to use their mistakes as a learning resource. In this grading method, the test is returned with each question simply marked as "right" or 'wrong." Students can then go over their exams and resubmit them with separate corrections, where for each wrong question they must identify the error, decide how serious it was, and describe how to fix it. The exam and corrections together are graded, and for each error correctly identified, classified, and fixed, the student gets back half the points lost. I implemented this in two applied calculus classes for non-majors in spring 2006 as well as in a year-long calculus sequence for engineers in 2006-2007. It was very well received, as indicated on the surveys the students filled out after each in-class exam. Most students indicated that, compared to traditionally graded exams, they spent more time going over their exam and felt they learned a lot more from their mistakes. In this article, I discuss the details of the grading method, the logistics involved in administering it, and the results of two years of student surveys assessing its effectiveness. Insofar as this method encourages students to actively learn from their mistakes, it is well worth the time investment on the part of the instructor. (Contains 1 table.)