As an alternative to baking your salt dough ornaments in the oven (or if you do not have an oven), you can allow your ornaments to air dry on parchment paper or wax paper in a place that has low humidity. This may take from a few days to a week, but they will eventually dry and harden. Make sure to flip the ornaments once per day. If you have the extra time and space, this is a nice way to save on electricity as well.