a serrated knife
Hit up the second hand stores! Time to get some old white curtains and make them look even older. And less white.
Step 1: Rough it Up
My curtains were almost a sheer nylon material which worked in my favour because I was able to produce some great runs and pulls in the fabric with a serrated knife.
Don't be afraid to make larger tears and holes. Experiment with movements of the knife against the fabric. Scrape the length of the knife sideways along the material, draw it down, press harder in some areas and you get different patterns.
If it's a heavier material, use scissors to cut holes into the fabric.
You may find it easier if the curtains are actually hanging up while you do this. I brought my curtains outside to the clothesline.
Step 2: Spray it
Take a spray bottle filled with strong, cooled tea (2 bags per cup of water) and spray it in patterns on the material. Let it drip.Go heavy in some areas and lighter in others.
You end up with a stained, aged, creepy curtain.