Hi David,

Phosphoric acid is used in socalled "rust removers" on steel so if you find it works as a pickle, why not use it. I use citric acid for pickling and then dip the work in a sodium hydrogen carbonate solution to neutralize the acid before rinsing in water.

Thor

It's quite cheap on ebay, I got a gallon for rust removal & find it as good as jelonite & a lot cheaper, I had some sheets of copper stored in the workshop & where they were on the damp floor it turned green so far up the sheets so I tried phosphoric acid with a scotchbright & it came up a treat,[didn't seem to harm the copper] so I use it for cleaning brass as well. No doubt someone with more knowledge will let us know if it has any undesireable effects..

Your thinking of hydrofluoric acid roy, we used it in the embossing dept to decorate glass for old fashioned pub windows along with brilliant cutting & sand blasting,some beautifull designs were made with it.