The "easiest" way is to create a teardrop on the texture map and create an appropriate bump map - that or put them in post-render. I know a few other people tried props, but I've only seen one that looked decent and that was a while back. Solo might have some pointers, since he (?) seems to be able to get a "wet look" on figures. I've also seen some decent results in Bryce; if you have that, it might be your best bet.