Well.. You can't.. But this might help, it is something i posted in the forum, but I only got little, and not very positive respons to it. Anyway. I will give post it here also if anybody wants to read it:

Today on my way home from school I walked passed a homeless guy who were begging for money, and I wanted to give him some, but I'm a poor student and don't really have any money to give. So I just hurried past him and tried not to catch his attention. But it really bothered me that I was unable to help. Then later when I was returning some bottles in the supermarket I saw something that inspired me. Right under the "print receit" button there was another button witch if you pushed would give your "bottle-money" to a charity organization (I believe this one was for Unicef). And here comes the point: what if the money we can make from putting commercials in the loader screen could be donated to a good cause?

And this idea really got me excited because next to the obvious fact that charity is a good thing. Think about the publicity possibilities (the fight against breast cancer could be "newgrounds supports the boobs" :P). I think that this would be a really good thing for newgrounds image. And I wouldn't mind giving those few measly bucks my movies would generate to a charity. I mean, so far I wasn't even considering putting commercials in my films because I didn't think it was worth the effort.

So - what do you people think? Any good ideas as to how this could work?