https://www.scripps.edu/newsandviews/e_20060213/bleach.html
“Bleach can expire. After a shelf life of six months, bleach starts to degrade. Even in its original bottle, bleach becomes 20 percent less effective as each year goes by.”
As long as there is a drop in the jug, I’m using it. Better than nothing.
I have opened old but sealed bottles and it was basically just salt water.
I want to look up hydrogen peroxide also.