ageekandfreak:

just-shower-thoughts:

If poison expires, is it more poisonous or is it no longer poisonous?

The expiration date would have to match the calculated allotted time for a an accumulation of denatured material to reach a given concentration at which the poison is ineffective, or more effective than it previously had been.

So, it ultimately depends on if the poison will denature in a sealed container within a reasonable period of time (>10 years), and produces a denatured product or products that will increase or decrease the toxicity of the poison.

I think that it would be an extremely rare occurrence to find a poison that will completely denature to create a solution, precipitate, or solid of only non-toxic products within a period of less than ten years.