Re flux pens, I have been using a Kester 951 pen, but recently noted that, according the the fine print on the pen, it has a shelf life of 1 year @25'C. Mine is dated 2017
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Re Veroboard/stripboard, I had not heard that they are coated with anything; I always clean them well with very fine steel wool and IPA before use, and that seems to work out ok.
As I don't use de-soldering braid very often, I find myself trying and failing to use stuff that is "old". Some effective homebrew concoction would be useful.
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