Fuji - I recently noticed there was a pink (cytomax) gunky build up on my H20 bottle spouts too. My solution was to soak them in hydrogen peroxide with the spout in both the open and closed position, and scrub the crevices with a toothbrush. I have vowed to clean my bottle tops promptly now, so the cytomax gunk doesn't solidify so seriously. but the hydrogen peroxide was great. Tokie