Here are two samples of cards made using vaseline as a resist.
The technique is as follows: Paint a piece of paper or cardstock with acrylics, let dry. Apply your stamping. You can also color the stamped image now, with some markers or so. You then lay down a very thin layer of vaseline on your image. This will act as a resist. Paint over the whole image with a lighter shade of acrylics and let dry. You will then be able to remove the paint over the vaseline layer. I learnt this technique in a book called Art Specially For You.
The fleur-de-lys was done in a similar way, but with one variation. I actually put the vaseline on the fleur-de-lys stamp and stamped it down on the first acrylic layer. This works for bold, non-intricate images.