It strikes me that I've never tried cotton balls and thinned silicone for decayed flesh texture. This is inspired because I was doing some work with silicone caulk earlier, having both bought a new hitch tongue with a 1-7/8" ball and assembling the bandsaw, and since I needed to clean some caulk up and I had recently opened a new bottle of Tylenol PM, the cotton wadding was handy. Coming back to it after curing, it's got an interesting solidity but also rips easily-- it would probably be better with something like Dragon Skin, or at least something that's not going to move a lot.
What I usually use for the corpses is latex and stretchy spiderweb polyester, but cotton balls work well for the smaller features like the face, and are fairly easily stretched into the form of the facial muscles. It also dries into a decent base color for decayed flesh, and accepts water-based pigments well, though it is pretty opaque. The silicone instead would be an interesting experiment, and since the clear silicone is fairly translucent, it would probably work really well for alien flesh, or something more recently dead and less decayed. I can also tint the silicone a much wider range of colors with oil-based pigments.
I should also try it with paper. One of the little-known secrets in sfx is that paper bags (or sheets of kraft paper) crumpled up then wetted and dried make a convincing-looking aged leather.
Bed now, again.