Just a question, why use cornstarch for your packer? Will flour, or baby powder not work? 

Baby powder, flour and corn starch all work. I have used them all. The flour sticks more (not a good thing) so you have to get off the excess.... but yeah it works.

I use baking soda/powder. Both of those work for me.

Most baby powder is corn starch ...

Ok, thank you for the replies. I just didn't know if corn starch was specifically better than other things.