I'm old enough that I used to make and cook starch on the days laundry was to be done. The above cook method was used. I think we have moved beyond the cooking method and commercial starch is available. I steer clear of the spray because of the overspray and the propellant-it can't be good for anyone's lungs. You should not store starched fabric for any length of time-it seems to invite chewing friends in some climates. So, make your starch, dip the fabrics you plan to use in it, roll it up for a while, iron it. When you are finished with the project dip remaining fabric in water (I put it it in a mesh bag an put it in the washing machine) and put it away for the next project.