While working on Deathsleet today (the fifth target on my 6MMRPC Hit List), I decided his base could make use of a part of the Water Elementals set from Bones II: 77312 Wall of Ice.
First Look: This piece required very little cleanup, and the hard edges of the crystals made it easy to remove the minor mold lines. As part of the Water Elementals set, the Wall of Ice is made of translucent blue Bonesium. However, the blue was far too saturated to work well as ice (more akin to sapphire), so I decided to simply paint over the entire model.
Painting: The piece was painted with a mix of blue and gray (VGC Electric Blue, Sombre Grey, Ghost Grey), and a light gray (VGC Wolf Grey) at the base to emulate snow and match the base for Deathsleet.
Conclusion: I'm surprised at just how well this turned out! I did an image search for ice crystals to get a general idea on colors, though ice being what it is, the colors of the environment were the determining factor. I decided to go for an icy blue look, and I think it worked quite well. I think this will add a nice piece of interest and color to Deathsleet's base.