Kenyonbm is right about sodium azide. It is also very poisonous. I doubt these days it would be easy to get anyway.
Plus, the post said the sodium azide was just used as an fungicide. So, if you are making your own fluid, you don't need it - just make a new batch if it goes bad.
Plus, the post said the sodium azide was just used as an fungicide. So, if you are making your own fluid, you don't need it - just make a new batch if it goes bad.