If you recycle the Alum. tank. Alum. on a scuba tank is Medical Grade and will bring in a higher price per pound. But they won’t let you know that and probly even deny it. The valve on an alum. scuba tank is worth more then the alum. also. So don’t give away the valve either. Your LDS will be glad to get rid of your tank for free as a favor. DAAAAAAA ! Valve $25./Alum.$35 = $60 profit.