To ensure a good adhesive bond, both your device and part need to be thoroughly cleaned. This may take some time, but the results are worth the effort.

Remove large chunks of adhesives with your fingers, spudger, plastic opening tool, or tweezers.

Don't use metal tools if you're cleaning display panels or glass covers, as the tools may scratch the surface.

Use adhesive remover or isopropyl alcohol (>70%) to remove residue from metal surfaces. Wipe in one direction with a lint-free cloth or coffee filter until all the adhesive residue is gone.

While isopropyl alcohol is generally safe to use on electronics, they will dissolve certain foam adhesives. Be careful to contain the alcohol when cleaning.

Allow the alcohol to completely evaporate from the device before reassembly.