I use alum exclusively for pickling in our studio. No acids or
other toxic chemicals. It is very simple and safe to use
-you must have a stainless steel pot or a copper pot -put the 1
tsp. of alum in the pot with about 3 cups of water -if you have a
stainless steal pot you must put a few grams of copper in the
pot -you then put the pot on a burner and bring to a boil for
about a minute or two.