As far as I know this only works for 4th generation. It may also work for 5th or 3rd or whatnot but idk I only have 4th
Go to settings.
Scroll all the way down to the bottom and tap Triple-click (double tap the picture if you need to see what it looks like).
You should be here.
Tap 'invert colors'
Press the home button 3 times
If you take screenshots it comes up normal so I've cant show you what it looks like.. You'll just have to try it and see:)
- iPod touch (4th generation)