Elmer's glue
Sta-Flo liquid starch

Mix well - 2 parts glue to 1 part starch. Mixture will need to dry out a while before it is workable. It may be necessary to add a touch more glue or starch. Do not make on a humid day! Store in an airtight container.

NOTE: This homemade version is just as nasty as the commercial variety. Beware of contact with clothes, carpet and hair!