I've found several ideas to try in the October issue of Martha Stewart Living. My favorite thus far is from page 148, "Skeleton Crew". I tried it out and here's my tale.
Now comes the gooey part.
Make sure your table is covered in newspaper or plastic and that you have removed all of your jewelry. I skipped this step and had to thoroughly scrub my table and clean my rings. It gets into every crack and crevice.
Then unroll your plaster cloth and cut into varying sizes. The longer they are, the easier, is what I found. I cut mine into 16" and 5" pieces. You'll want to make most of your cuts before you start wetting as your fingers are soon too gooey to pick up the scissors.
Following the manufacturers instructions, dip the cloth into warm water. Martha says to add tea for a stained effect, but I admit, I forgot and didn't do this. Will try it next time.
One helpful tip is to keep working the fabric in the water/tea until it gets a little gooey. It will adhere better and also dry with fewer holes.
Cover all of the newspaper and add layers to anything you want more definition.
Let dry in a warm place and voila! Giant bones ready to add to your favorite haunt.
I got my plaster cloth from Michaels, it is called Rigid Wrap. They had two sizes and the larger was easier to cover large surfaces. I used one large size for three bones and two small sizes for the same. This cloth is great, I'd like to use it for other crafting projects.
Let me know how it works for you!