Ready to roll icing - can you add liquid food colouring to it?

[JoshandJamie]

or does it have to be that paste stuff? I want to make black icing for mini skull and crossbones on cupcakes (pirate party) and have read to roll icing in white and black liquid food colouring but am not sure if you can add the liquid stuff to the ready to roll stuff. Any ideas?

Thanks

That is the most fabulous tip I have heard for black icing ever! It is now stored and locked tight in my memory bank! Wow!