if i remove them then there's only a black spot under them
Well you don't just have to use C4Ds.
You can try to get some Abstract brushes from DevianTART, and use those.
Or splatter brushes set to a mask (to do this, you put the splatter where you want. Then make a new layer, go to image>apply image, and press ctrl+alt+g. Move around the apply image layer to your liking).