Just tested out the 5l kodak c41 final rinse from unique photo-negatives were the cleanest I've ever seen. No spots whatsoever. I am definitely using it from now on. Even though it is quite foamy and there were still copious amounts of bubbles on the negatives when I hung them to dry, there is absolutely no residue (other than what looks like a tiny bit at the bottom of the roll where everything dripped to).