A little while back I bought a huge tupperware container to sanitize bottles and remove labels. I filled it up with water and added the appropriate amount of ammonia and added bottles. After a few days, it worked like a charm and most of the labels had fallen off. So I've continued to use this technique, however, I've been noticing something I can't explain. About half my bottles exhibit a white residue on the tops and inside the bottle. Almost like salt. You can scrape some of it off, but its pretty resistant. Has anyone else ever experienced this? Is I put beer in the bottle, is it going to be bad for someone to drink?