We used it (Dawn) on Imafink's last Saturday and it didn't seem to affect the black plastic one way or another. It did eat all the wax off his car which is what we were trying to do. He had some stuff (I think it was Back to Black) that did darken it up. He put it on with his fingers and the plastic got nice and dark. I think it mighta eaten his fingers off though. Seriously FP I think the answer to your question would be no. It just works on them pads.
Pat