Stating the obvious, but, how do I get all my greasy finger prints off my screen? (Or for that matter, any kind of the usual dirt).
Turn off the device, and use a soft, microfiber cloth. It may be slightly damp, but do not soak it. Make sure not to allow any water to seep into the device, especially through openings like ports and jacks.
Refer to Apple's cleaning instructions for more in-depth explanations.
If you have eyeglasses, then you know that dry clean does not work so well.
Go to an Optician store (where they sell eyeglasses).
Since most eyeglasses have highly sensitive coatings and are exposed to human contamination.. residues etc.. they have the right solution for cleaning.
They have a correct solution mix (in a spray bottle) with microfiber cloth to clean glasses and it is as good for the screens.
This would do the true clean.
Rubbing it on your clothes would only spread the finger's grease around but it works temporarily.
Needless to say, humans are a big source of dirt and grease. After multiple uses of microfiber cloth, wash it in a washing machine to remove all the grease it has collected.
I always flip mine over and rub it on my jeans - but the act of putting it my pocket is usually all the wiping it needs. Yes, it could get a scratch if my jeans had grit on or in the pocket (though it never has).
When really greasy fingers or food spills are on a screen I will use ammonia-based window cleaner, methanol (camera lens cleaning kit), ethanol (methylated spirits - same thing in the optician's spray basically), kitchen spray, isopropyl alcohol or just about anything else that will shift grease.
Nothing lasts forever and life is too short to be precious about an iPod.
This is indeed very important questions as it encompasses the very basic human affinity towards cleanliness.
A considerate individual shall always keep their iTissues handy for such an occasion. Those ingeniously designed in California pieces of space-grade cloth will leave your iMac, iPad and even the iPod's screen in showroom condition.
Now available for Retina displays as well for as low as $14.99 at your local iStore.