Availability of 8.3% Bleach Is Nil

[Palmyra]

So long as it is stored INSIDE the store (below 80 deg F), it should be fine.

I looked at the bottle I have; how did you decode the date?

The Walmart Great Value bleach has a format of 18 219 13:40 S2 CA-01 so it is [20]18 219[th day] or Aug 7th... ie. (08-07-2018). I suspect (13:40) is military time, but I have no idea what the (S2 CA-01) means.

I don't have any of the 10% chlorine, so I can't check that, but it will be a similar scheme.

As for calculating the half-life of chlorine bleach, due to age and storage conditions, I think ChemGeek had a spreadsheet on the web, somewhere.... (My recollection is that at about 80° F the half life is about 6 months, but I stand to be corrected.)