Sorry - I'm afraid I don't. However, I do know a fairly cheap way of getting rid of really dark paint (dark purple - I was obviously having a crisis!). Rather than spending a fortune on all the coats of paint needed to get rid of a dark colour instead I opted for wallpaper as it was only on one wall. I know I know, it's all the fashion and surely becoming really really dull now but actually it looks great and didn't cost that much at all.