I use San Ji soy sauce bottles for Dektol with a bit of Saran wrap under the cap. Cleaning the darkroom the other day I found a bottle from 2000, the "sauce" in this bottle is still clear (with a bit of precip. in the bottom of the bottle). These bottles have nice long necks, when filled to within a centimeter or so of the top, there is very little air in the bottle to promote oxidation. I opened one a few years ago, the plastic wrap had a small indentation which I surmise meant the bottle was sealed and the sulfite had scavenged the oxygen in the head space at the top of the bottle and the seal was good enough that a slight negative pressure caused the dent in the plastic seal. It was still good.