I used a hot water bottle with towelling cover, resting on it for about 5 minutes. glue softened at 45 degrees. enough to easily lift panel.. Ipod’s working temperate is 55 deg C max according to apple. I used IR heat gun for temperature check.
For many people it is worth cleaning out the muck & “belly button” fluff from the fan while you are in there. Adds on another 10 mins to the job and does wonders for the cooling system. Cheaper to clean the fan than to replace burned out boards etc