One of my favorite Youtube channels is Luvleescrappin. She has all kinds of homemade tricks and many tutorials on art items. I like so many of her tutorials I can't even pick my favorite.
I did stumble across this one some time ago. This one teaches you how to make your own modeling paste. I put it in my favorites on youtube because at the time I had modeling paste. Yesterday I ran out and decided it was time to try Leeanne's recipes and make up a couple of batches.
You really should watch Luvleescrappin's tutorial. It is detailed and she is entertaining. Here is the link........http://www.youtube.com/watch?v=BX9XRhcw6ao
Now that you have watched Leeanne do her magic, I will tell you that I followed her small batch recipes. I made one with baby powder and one with baking soda.
I encourage you to make some and see which you like better. So far I like the baking soda one the best, but I am going to keep trying them both until I am out of what I made up. From there I intend to only make the favorite one.