My primary bucket has become stained and retains a strong hop odor. I tried to get rid of that stuff once, filling the bucket with hot water on top of 1/2 cup of Oxi-Clean. It worked pretty well, getting rid of the stain and most of the odor. But of course the stain & strong odor came right back in a few more batches. So- I figured stain couldn't hurt the beer, and beer's gonna smell like hops anyway, so I just clean and sanitize the bucket, and continue brewing. So far, it works.......
“Malt does more than Milton can / To justify God’s ways to man”
-A. E. Housman (1859–1936). A Shropshire Lad , 1896.