[Ron Wood]

I found an old formula. I do not know how well it works or any particular process to apply it:

Nitric Acid- 4oz.
Hydrochloric Acid- 3oz.
Iron(clean nails) �½ pound
Water(distilled) 1qt.

Acids are mixed together in crockery or glass pot (out of doors!) and nails added. After the nails have dissolved, add water and put into colored/glass stoppered bottles.

I am a little troubled by the part that says "add water". You must be very careful when adding water to an acid solution since there can be a very vigorous reaction (with pure acid it is almost explosive) so I would suggest you must add the water very slowly a little at a time to prevent the acid from splashing all over everything, particularly you.

If you have not already done so, you should also try to find some instructions on rust blueing as it is a rather simple process but requires many steps that involve careful preparation and application.

I hope this helps. Perhaps there are other forum members who can provide more authoritive support.