Well, this is what Nintendo of America says:
- Do not use any solvents or cleaners of any kind.
- Do not submerge the system in water or other liquids.
- Do not pour water directly on the screens.
What to Do:
- Slightly dampen a soft, cotton cloth with water ONLY and wipe off the Touch Screen and 3D Screen.
- Using a dry portion of the same cloth, wipe the screens dry.
- Using a loop of transparent tape, dab at any remaining dust or smudges. (I never do this step)
- Repeat steps 1-3 if necessary.
You need two things in order to get a Friend Code.
After that, you click “Orange Smiley Face" on the top row of the touch screen, and some instructions should come up. Follow them and you should be able to get your Friend Code.
Side Note: Page 39 of the 3DS XL Manual and Page 36 of the Original 3DS Manual has the information/pictures about it.