Removing part of an image

Hi everyone.  I'm hoping someone can give me a quick fix.  I have a vector image.  I am using it to make a vinyl on a t-shirt.  I can ungroup the whole image but some parts of it need to show the -tshirt through it when I  make a mock up.  The parts in grey can be removed  on the image but they show black.  I need to remove them to show the shirt I'm laying them on.  Essentially instead of grey, I need them to be clear.  Any ideas.   This started as a vector I converted to bitmap, then simply quick traced and ungrouped.