Yes, chemical containers can be refilled and reused once emptied. However, the new liquid used will need to remain the same as the tank's original contents. Once poly tanks have been used for fertilizers, pesticides, or other chemicals, alternating between substances should most times be avoided. This is because harmful residue can be left over without advanced cleaning methods, even in small or barely visible amounts. We advise purchasing a new container for new applications. Never consider a container potable once used in a non-potable fashion.