What type of hair did you use (human or synthetic) and why do you think the curls will fall off? I ask because even synthetic wigs have washing directions that state what you need to do in order not to lose the curls.
There are people who do the "no shampoo" routine so if you do a search, you may see what they do and perhaps adopt that. Other people use I think sea breeze. Otherwise I personally think there has to be a way to wash your hair. And if the curls drop, I'm sure you can set them either with hot water or the curls will return if you don't manipulate your hair. If the hair is human hair, then you have nothing to worry about as a curling iron will do the trick.
