Remove the battery from the device.

Reusing a deformed or bent battery after it has forcefully been removed is a safety hazard. Replace it with a new battery.

Before installing your new battery, peel up all the old adhesive and remove it from the phone.

For best results, clean the area underneath the battery with isopropyl alcohol and a lint-free cloth or coffee filter. This helps prep the surface so the new battery can adhere more strongly. Replace old adhesive with stretch release adhesive strips, double-sided tape, or pre-cut adhesive strips.