Just picked up a brand new 5 gallon slim torpedo keg. I filled with hot water and 2 scoops of PBW, let sit for 2 hours, then rinsed with hot water and scrubbed with a carboy brush. I was about to fill it with beer and gave it a quick sniff, it has a metallic smell which I do not want to transfer to my beer. What should I do with my second round of cleaning? TIA!!!