Glass bottles. I came across a yard sale several years ago and bought six one gallon jugs, two half gallon jugs, and about 15 one quart bottles, all dark brown, for $5. I also bought some dark brown glass bottles with large mouths, 250ml, from a guy on ebay. He sells 84 of them for $10 (and $30 shipping). I decant colour developer and blix into these bottles filled right to the top. Chemicals keep very well in the smaller bottles with no air space. By the time I have used up the developer from one small bottle, it is just starting to turn colour due to oxidation, but still gives excellent performance. I use single solution LORR dev and blix from Kodak. Works great in rotary tubes and real easy to mix.