There are things that I like to use nitric acid for and when I need it, I
just make my own batch up to use. It is easy and in fact, I have another
batch mixing up in the wash room so I can do some silver refining or gold stripping by dissolving the base metals from under a gold plated surface.

 All that needs to be done is mix some sodium nitrate into sulfuric acid(car battery
or drain opener). It works out to about 1 quart to 1/2 cup sodium nitrate to make a mild nitric acid.  Pre dissolve 1/2 cup of sodium nitrate in 16 ounces of hot disstilled water and mix this with 1 quart of sulfuric acid. This works with either type of acid. Just give it about 15 mins to combine. If it is too weak for what your working with, heat it on a hot plate but DO NOT boil. Boiling will drive off the nitric acid in the steam.

If I wanted to make it stronger, then it would be boiled and run through a condensing coil like one would make whiskey! :) The condensed liquid is close to a 70% nitric acid

be sure to vote for me! thanks, Dr Charles