The plastic part on the top of the iPod.
Carefully insert a small flathead screwdriver in the seam between the metal casing and white plastic top. Use the screwdriver to pry up the white plastic top bezel. Be careful not to damage the soft plastic with your screwdriver.
To make this job easier, heat up the adhesive with a hairdryer on low heat for a few seconds.
Lift the top bezel off of the iPod.