I thought these had gone out of favor for food because of the silver(nitrate?), that has bled into the plastic, or is there a way to clear them now?
I'd calculate the risk like this.
What weight of silver nitratre can get bled into the plastic.
Thought, the weight of the canister is only a few grams so the silver nitrate component would have to be measured in milli of micro grams.
How much can be bled out again.
Thought, a lot less than bled in, and given an initail couple of washes to get rid of that more easily bled out even less That'd leave the little that can be bled in minus what is left when no more can bleed out easily and also minus that which cannot be bled out ie the silver nitrate that's still in the plastic years down the line. I guess this " potentially available to potentially do you harm" amount is going to be measured in micro or nano grams.
Over what timescale?
Probably several years.
So now we get to ask the important questions like what quantity of silver nitrate would it take to do us harm?
As a gauge I'd look at photographers developing their own prints, who will be absorbing magnitutes more silver nitatrate that someone storing a few spices, if there's not a major problem for them the problem for the average bushcrafter would seem to be almost (if not completely ) nonexistant.