If the scratches are not that deep, you can try to buff it out. If that does not work, then you should replace the back plate.
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If the scratches are not that deep, you can try to buff it out. If that does not work, then you should replace the back plate. If you need help replacing it, you can refer to the troubleshooting page: https://www.ifixit.com/Wiki/Moto_X_Pure_Edition_Troubleshooting