Im wondering if anyone knows a safe way to remove dirt in your screen. Its inbetween the lcd screen and the protective screen of the top one. I'm wondering if theres a way to remove it without taking it apart.
Or if so how much would it cost for nintendo to clean it.

How the heck did you do that? Nontheless, call Nintendo, and tell them you have a warrenty. The number will be on the back of the DS. Sorry, but that's the only way without voiding the warrenty

Well I would try to...hold on here's what the manual says:

"1) Turn the DS off, and hold it at a vertical angle.
2) Using your thumb, apply light pressure to the DS touch panel. This will create a gap along the edge of the housing to allow the brush to clean more effectively.
3) Work the bristles under the housing edge and gently move the brush from side to side, removing any dirt or debris present."

I hope this helps out with your problem, if it doesn't try contacting Nintendo by telephone or email.