Colour-coat

To dress up something nasty so as to make it more palatable. Updates the anachronistic phrase, "You can't make a silk purse out of a sow's ear". Essentially, while brown is an amalgam of many colours, the process of separating colours into Red, Orange, Yellow, Green, Blue, Indigo and Violet creates an object which is pretty on the outside but, nasty on the inside.

Hayley: Well you know me, I don't colour-coat things!
Adam: WTF?
Hayley: Eat seven different colour fruits and poo them out, it's still poo. No matter how you colour-coat it, it's still shitty on the inside.
Adam: That's disgusting!
Hayley: So you know what I mean - you've tasted it before?