A while ago I made up a tub of mild paint stripper, 50 litres of water and maybe a kg of 100% NaOH, and used it to remove the paint from 3 or 4 small items. Recently I needed to use the paint stripper again but over time the water had evaporated leaving behind a thick skin of white crystals on the floor of the tub.
Not a problem, refill the tub with water, break up the crystals and stir them back into solution. Put painted item into tub, remove a day later, hose off the paint except that the paint does not budge. The paint hasn't softened or wrinkled it doesn't look too much different to when I put it in the tub.
This is probably not a surprise to the chemists on here, but what has happened to the NaOH?


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