This conversation is making me think about a different tack. Recently I've been playing with soaking regular developing paper in KN03 to make a sort of weak printing out paper. With all that silver dissolved in the used fixer, I wonder if there is some way to use it directly instead of trying to recover it as a solid metal. Something along the lines of coating a paper with sodium chloride and potassium nitrate and then soaking it in the used fixer to re-use the silver for photographic purposes ( I do realize there is a nonsensical aspect to this thought... the fixer is for removing the unconverted silver from paper in the first place... I want to put it back onto the paper for re-use instead! )