Remove the battery.

Before installing a new battery, remove all traces of the old adhesive from the frame, and clean the glued areas with isopropyl alcohol (>90%) and a lint-free cloth.

During re-assembly, temporarily re-connect the battery to the motherboard to help align it correctly. Disconnect the battery after it is seated.

When reassembling your phone, replace old adhesive with stretch release adhesive strips, double-sided tape, or pre-cut adhesive strips.