Yes they can be reused. There are commercial sizes, that get reused. I have some old bags of desiccant labeled "Desicite" by Filtrol. They weigh about 1.5 lb. and the reactivation directions are printed on the bag. 245-275 deg F. for 12 hours. If I'm in a hurry, I have even microwaved them. I don't think that the little ones that we find in product packaging would take that much time and temp. I think that when the wife is done baking and the oven is still warm I would put them in until it cools off.