Wow !!!!!!!!
That's why acid like this shouldn't be available for general sale to the public.
Hydrochloric in the first instance is the incorrect acid to use and at the strength you've suggested it's basically a lethal BOMB.
You are so lucky that you didn't do yourself some serious burns.
Sulphuric acid is the normal de-rusting acid that's used in industry. It's known as a Pickle Bath and it should be around 5 to 15% in strength. Also oil is not to be induced into the bath as it acts as a barrier at that percentage. Oil must always be removed from the items prior to immersion. Also the solution should be heated and not cold.
One last thing, there's an old saying when mixing acids etc.
"Do what you oughta and add acid to water" never the other way round as that will cause an instant explosion which will cover you with serious acid burns.
Why do I know all this you ask ? well I was an apprentice Electroplater and worked in one of Australia's best plating shops in South Australia and safety was something our maintenance guy "Bill Topper" (now deceased) whom I worked with for months on end was always paramountly insistent of. Yes I nearly blew myself and the shop up and had people running when I broke the golden rule. So you're not alone in that department.
BTW I'm not trying to be a smart arse, but I can't stress enough the safety factor when playing with acid and alkaline solutions.
Cheers,
BB.
