well.. the spots where the background is black is really easy.. you just go over the watermark with black paint. The other parts I use either the stamp tool to match the background (if its not a solid color) you select the stamp tool and stamp on a spot near the watermark (must press alt while you stamp) then select a brush and go over the watermark.. OR.. I use the eyedropper to click a spot right next to the watermark to get the exact color then use the brush to go over it.