Dear Tracey,
Bowling crony is right. I would add something to what s(he) has written. Take some 99,9 % alcohol (the one you can use for cleaning CD/DVD lenses). Plunge the DS completely (w/out cartridge and battery in it). Leave it for a minute and then get it out & shake it to take out the liquid. Put it in a room with constant warmness. It will avoid that parts inside will oxyde. Furthermore, if you have some scratches on your DS screen, you can use some neutral polish (the one for cars). Paint carefully your screen and wait 20 minutes. Use some cotton (like demakeup) to "clean" the screen. Your DS screen will look brand new. I hope it helped. Gameically Yours, Kikilon
Kikilon, May 2008