We're getting ready to keg our first brew, and we're working with a ball-lock corny leg that was given to us. The liquid dip tube and the lid had a really nasty smell that I assumed was the o-rings, so I got rid of them. I just did an overnight PBW soak and the smell is gone from the dip tube, but the lid still has an awful, somewhat metallic scent. I'm not even sure how to describe it. Any ideas?