The iPod Touch 4th Generation front panel is attached to the rear case by adhesive. The use of a heat gun to soften the adhesive is highly recommended.
With the heat gun set on "low", begin heating the lower portion of the Touch near the home button.
It is suggested to heat the desired portion in a circular motion pattern to evenly dissipate the amount of heat throughout the device.
When there is enough room to grab the bottom edge of the front panel, lift the front panel away from the body of the Touch to peel up the adhesive along its left and right edges.
If the adhesive is too difficult to separate, use a heat gun to soften it before proceeding.
Due to the construction of the Touch, the digitizer cable cannot be disconnected until the logic board is removed. Use extreme caution when handling the front panel assembly, as it is attached to the rest of the Touch by the very delicate digitizer cable.
The display data cable is very short and is connected to the logic board near the top of the front panel assembly. If it does not become disconnected while freeing the top edge of the front panel assembly, be sure to disconnect it with a plastic opening tool before rotating the front panel assembly out of the Touch.
Carefully pull the top of the front panel assembly away from the adhesive holding it to the Touch, minding the short digitizer cable connecting the two components.
Being careful not to rip any ribbon cables still connecting the two halves of the device, lay the device out so that you can access the back side of the display assembly.
Insert a plastic opening tool under the rubber holding the home button in place.
Slide the tool around the perimeter of the button, prying up as you go.
If you follow the guide from the bottom to the top, you can reassemble the device. If you disassembled the phone farther than the Home Button guide shows, go back to the device page and follow the guide that matches your device.