Background: Ongoing masking of K-12 children has not been universally accepted despite recommendation from public health authorities. In states without universal mask mandates for schools, district administrators are forced to make masking decisions under significant local political pressures. There is a call for endpoints to masking to allow communities to tailor mitigation while keeping schools safe, focusing on harm reduction. Methods: We reviewed existing measures for the safe opening of schools and designed a stepwise, accessible approach to the removal of masks in the K-12 setting. Results: Focusing first on the assessment of school impact due to COVID-19 disease and then considering the context of existing community transmission levels allows for a metrics-based approach to masking that is flexible and practical, enabling school officials to adapt quickly to the pandemic landscape in their communities, independent of political pressures. Conclusions: While this proposal is preliminary, a dynamic metric system for masking may encourage those communities who wish to minimize masking to adopt masks during highest risk periods, protecting against SARS-CoV-2 transmission in schools and allowing for more holistic harm reduction. This approach may serve to guide districts during times of uncertainty when central guidance short of universal masking is lacking.