[Cletus.D.Yokel]

H2O2 “decays”.
The extra oxygen is not stable and is easily freed to combine with other O molecules to release as O2 gas.

H2O2 turns to H2O in a relatively short time.
Check the date and trust it.

[cherry]

bleach and hydrogen peroxide are not shelf stable....I know there are chlorine tablets of some sort that have a better shelf life....

do what the old people from the old country used to do....drink pickle juice....the vinegar is stable and its just darn good....probably as protective as anything ...