Use tweezers to peel away any remaining adhesive from both the rear glass and the phone's chassis.
Then, clean the adhesion areas with high concentration isopropyl alcohol (at least 90%) and a lint-free cloth. Swipe in one direction only, not back and forth. This will help prep the surface for the new adhesive.
|[* icon_reminder] Follow [guide|47490|this guide] to reinstall the rear glass.|