Surplus bottles from things like: My kids cough syrup, vitamin
pill bottles, mouthwash bottles, bread machine yeast bottels
(220mL- perfect for storing developer for my single reel size of
steel reels tanks).  Yes, pop/soda bottles. Low air permiability
to keep the fiz in keeps stray air out when repurposed for the
darkroom. Remove original labels, and re-label clearly.