Have you tried Smooch or Smooch Spritz?
Smooch is a pearlized ink that adds color and shine. It works similar to acrylic paint, and has an applicator similar to a nailpolish brush. You paint on your stamp instead of inking it. Shake well before using.
Smooch Spritz is a fine spray of the same product as above. It quickly adds shine and color to cardstock, paper. chipboard, wood, fabric, acrylic and more. Since it is similar to the ink in metallic ink pads, it gives a different look than spritzing with classic ink. Works great with stencils. Shake well before using.