Your iPod Touch’s apps, Web browser, calendar and music are all activated using touchscreen commands. However, some of the most important functions are handled with one of three plastic buttons on the iPod’s outer shell: the “Home” button lets you quickly pull up the main menu, the “Volume” button controls audio levels, and the “Sleep/Wake” button handles all the device’s power and sleep options. If any of these buttons are stuck, you can unstick them with a little basic cleaning.
Dip a cotton swab in rubbing alcohol. Get the tip of the swab moist, but make sure you swab off any lose droplets of rubbing alcohol before using the swab, as you don't want to expose your iPod Touch to excessive moisture.
Swab the sides of the "Sleep/Wake" and "Volume" buttons, and work the cotton around the "Home" button in a circular motion. The rubbing alcohol eats through sticky residues without damaging the casing's plastic, glass and metal components. With button residue removed, the buttons should loosen up a bit.
Blow compressed air into the small seams between the iPod Touch casing at the buttons. Small cans of air are available at most electronics or hardware stores. If exterior gunk was not the culprit, your button may be sticking due to dust or debris trapped between the button and the casing -- compressed air flushes out this debris safely.
Take your iPod Touch into an Apple Store if the problem is still not resolved. When your buttons do not unstick after cleaning, then internal hardware problems could be to blame.