The first skull in both pictures is before latex.  On some of them I just changed a
little but on others I removed the lower jaw and really built up the features.
Here are some pictures showing the slot for coins that I covered over with latex
and paper towel or cotton. And on the right you can see I removed the lower jaw
and cover the hole with latex & cotton.
The skull on the  top I completely covered the lower jaw and made it bigger. Then
I added teeth. I also added the piece of wire that it hangs from.
On the left you can see I made the skull completely different. And on the right I
just gave the skull a few coats of latex. I also painted glow in the dark paint in all
the eye sockets and on the teeth. I wanted a bunch of skulls that looked different
hanging from the porch blowing in the wind. This isn't a major prop but it is a
nice add in to a display.
Here are some Skull banks I picked got from Rhode Island Novelty. There about 5
1/2" long & 3 1/2" high. The lower jaw pulls off.I added a wire eyelet so I could
hang them from my porch ceiling for my witches display. The center skull is what
they look like before I added some latex. I like the skulls with no lower jaw like
the one on the top left. I think I have 8 that I will hang.