I was getting ready to transfer to another carboy this morning, and noticed really light colored streaks in the unfilled carboy. I use PBW to CIP my fermenter(s), first scrubbing most of the beerstone away using cold water then soaking with PBW for at least 1/2 hour. then scrub some more, rinse, and either drip dry and put away, or acid rinse and fill. the streaks look like brush streaks since they are horizontal. but so light (can only notice when dry) I probably wouldn't notice if the same residue exists in a stainless fermenter. Is an acid rinse adequate when no "chunks" are evident, or is there a more thorough method I should employ? I have not had any infection issues in the past; have I just been lucky? Your thoughts.