Signing systems that attempted to represent spoken language via manual signs -- some invented, and some borrowed from natural sign languages -- have historically been used in classrooms with deaf children. However, despite decades of research and use of these systems in the classroom, there is little evidence supporting their educational effectiveness. In this paper, the authors argue against the use of signing systems as instructional tools. This argument is based upon research demonstrating that (1) signing systems are less comprehensible to learners who rely upon signs rather than speech, (2) signing systems are used inconsistently by teachers, and (3) signing systems often unintentionally exhibit features of natural signed grammar, leading to input that does not accurately convey spoken languages, which is the original intention of these systems. Instead, the authors advocate for a return to the use of natural signed languages in classrooms educating deaf children, with creative uses of interpretation to provide those students who may prefer or benefit from spoken English with its presence in the classroom. In addition, we note ways in which future research may explore how natural sign languages and deaf adults may benefit the educational experiences of deaf children.