I have a bottle of 24% silver nitrate solution and a bottle of 12% citric acid solution that I made up more than a year ago and they are still fine. I read that they keep better if you keep them separate, so that's what I did. Just about time to make more!
Thanks so far to those that have replied! I read on The AP site that for Vandyke they use Tartaric acid as an oxidant and so I was under the impression it was a preservative.
So is Tartaric absolutely necessary or can the AgNO3 be used/kept without it?