Like John said....be careful with muriatic acid...nasty stuff full strength for sure.
I have used it ( outside, it gasses real good ) to remove heavy rust from parts like rotors and drums. Then after rinsing with water and neutralizing with baking soda the stuff still develops a coat of rust, at which point I clean with phosphoric acid or media blast.
If you are just trying to destroy some of the new finish on zinc and phosphate bolts I would just experiment with some short dwell times to see what happens ??
Mike