Despite any other provision of this Act, it is not an offence against this Act for--
(a) a person to manufacture, produce, possess or supply a substance listed in Schedule 2 if the substance is contained in a product from which the substance cannot be readily extracted or readily synthesized, or
(b) a person to manufacture, produce, possess or supply a substance listed in Schedule 2 if the substance is contained in a product that is not for human consumption and the person manufactures, produces, possesses or supplies the product in connection with an activity that is not unlawful, or
(c) a person to possess or supply a substance listed in Schedule 2 if the person possesses or supplies the substance for the purpose of its disposal as waste or its destruction.