Is there a way to spray dye on already laid mulch. I have a customer who had 6" black hardwood laid on this hill 1 year ago. Yes I know it's too thick, but I didn't do it. He doesn't want to strip it, and there is too much there to add more. Has anyone ever sprayed dye over older mulch to recolor it? If so where can you get it, and what is the process. I am pretty good friends with the local mulch guy so getting some may be possible, but I would have to draw it from his 55 gallon drums.