If you're reusing your frame, follow this step to clean the thermal paste from it. If not, skip down one step.

Use the flat end of your spudger to gently scrape away large pieces of thermal paste.

If you're reusing your enclosure, be careful not to tear the graphite film.

Use a pipette or syringe to apply a couple drops of highly-concentrated isopropyl alcohol (over 90%) to the thermal paste residue.

Use a microfiber or lint-free cloth to wipe the frame clean.