Lay a heavy-duty black garbage bag flat on a work surface, open end toward you. With scissors, cut 1 1/2-inch vertical strips from the bottom, stopping a few inches from the top. Cut open one side seam, then unfold bag. Use masking tape or tacks to hang. Then, with hands a few inches apart, grasp each strand and pull; stretch strands in several places for a decrepit effect
Now isn't this the neatest and sounds so easy. If it looks like something you might want to try, here is Martha Stewarts' article and it came from her 2004 Issue of her magazine. I love finding fun ideas like this that are also easy on our budgets but really creative. Like i mentioned in my other post about her website, you will find literally 100's of wonderful Halloween ideas. Enjoy and let me know if you try it! Oh and read all the comments under her article too for helpful hints:) On of the hints suggest you use a super heavy duty bag and be careful when you are stretching it........Oh I love Halloween!