I'm making a purse cake next week and am making some accents with mmf.  I got a can of Duff's Cake Graffiti in silver to spray on the mmf to give it a silvery shine.  I'll also be piping a design with buttercream and was just wondering if I could spray some of this in the icing to colour it too and would that make the icing a shiny silver too so the icing wouldmatch the mmf?

AJust pipe your designs and then spray paint it.

My piping is going to be somewhat intricate with lots of small bits.  The main cake will be a different colour.  I don't want the spray to get on the main cake part so I can't just spray it afterwards.

AOh gotcha. Sorry but adding the Duff stuff to your icing won't work. Your best bet is to use royal icing and hand paint it silver once it dries (or you can use piping gel colored silver but that only works for simple piping such as dots).