I've just finished the Halloween decorations from salt dough, and I think they succeeded very well... they are quite superb!
I make the salt dough with mixing the salt and the flower half and half, then I spill some water to get a flexible material.
After I kneaded the dough I used Halloween cookie cutters to cut out different forms as bat, cat, spider, tombstone, pumpkin, ghost etc.
I made holes into the forms because I wanted to hang them up.
I dried the forms in the oven (not more than 100 degrees). It's very important to turn the forms from one side to another quite often to avoid the undulation.
And here are my not too frightening Halloween ornaments:
My other blogposts on this subject:
Miniature salt dough pumpkins for Halloween
Salt dough Halloween ornaments