Um...
Actually, you CAN delete your tracks, if you look through your NG Account page.
Well, I don't want to be too harsh, because I don't think you're meaning any harm or trolling... But this is sort of like drawing a random scribble on a piece of paper, then hanging it in a gallery because it resembles a butterfly. :P
Basically: The NGAP (Audio Portal) isn't a place to just dump random bits & crap, any more than the NGFP (Flash Portal) is. The only difference between them is that the NGAP has no Blam filter.
Anyway, just don't upload any old piece of Sfx crap, okay?