I used a permanent marker to disguise a scratch. Wiped it off the face before it was fully dry. Don't forget it will take on colour from whatever you are colouring over (a bit like watercolours).
I also coloured in some piping under a washbasin with a marker and it looks amazing! Well, actually it doesn't because it's sort-of invisible now against the dark tiles behind it!
The Story of Syd Barrett and Pink Floyd: Sky Arts
SNP and Greens end coalition deal