Response to cleaning damaged slides

Donald: I don't know if using acetic acid will solve your problem or not, but I do know that you should not use glacial acetic acid (or anything nearly that concentrated). It is not necessary, and is much more likely to harm the slides than duilute acetic acid. (I don't like to tout degrees, but I do have a PhD in Chemistry.) Urine contains ammonia, other amines, minerals, salts, etc. All of which are water soluble. The overall pH of cat urine is basic, but is not characterized as strongly basic. I would suggest soaking a test slide in a large amount of water (preferrably distilled, can buy in supermarket); I would also use warm water, since the E6 process is run at 100.4 degrees. This should bring most if not all the urine residue into the water solution. Then I would change the water and resoak in a dilute sloution of acetic acid (as a guess, even more dilute than stop bath, and probably at room temperature). Let the slide soak for a few minutes, and then rinse in clean warm water. As an aside...There are many reasons why you don't want to or need a concentrated acetic acid solution: (1) it is corrosive, and may destroy the dyes; (2) based on numbers, you don't need it. There is plenty of acid present in dilute acetic acid to neutralize the amines in the quantity of urine present; (3) as part of the acid + base = salt and water reaction, heat is formed as a byproduct. Using a concentrated acid, will result in a very loacalized generation of heat (probably right on the film surface), which could be enough to damage the emulsion. In a dilute solution, the water acts to "buffer" the heat, and prevent any localized heating. Good luck and hope this helps. Arnie

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