For bones like that, I used Games Workshop paint, Bleached Bone specifically.
I then ink the bones with Chestnut Ink Wash.
Once dry, I drybrush with Bleached Bone, adding white with every step, for two or three steps.
The real trick comes after the bones. Paint the mouth and eye sockets with flat black, and then go and pick out the teeth with pure white.
The contrast between the aged bone and the stark white teeth on black is what makes the paintjob work.