I'm in the process of restoring some of the hardware for the front suspension.

Some parts are new and some original. Nothing in horrible condition rust wise.

Even after I soaked them in the Vinegar/Lemon,
https://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=5632981&an=&page=&vc=1 I've noticed a flash rust beginning.

Is there something I'm doing wrong?

I even tried ECS RPM stuff after but it didn't help long enough except on brand new parts.

I'd like to re use alot of this (short of sand blasting) if possible.

Is Muratic Acid a better way to entirely eliminate rust at the surface from re appearing?

Yes, you are doing something wrong. You are using acid to clean the rust, rinsing with water, and getting flash rust.

Try using a non acid product li(not water) like Evaoporust. Parts treated with it and rinsed in thinner are ready for RPM and will be rust free. Remember, RPM WILL NOT work when applied OVER rust, you need to get the metal completely rust free before applying it.

For fasteners I dipped them in Muriatic acid. Once the rust was gone, they got dipped in baking soda water. If that's all you do then they will start to flash rust imediately. I dipped mine in EvapoRust for about 10 minutes, rinced with water and used compressed air to dry. I had them sitting in a tub on my kitchen counter for two weeks before taking them to the platers. They showed no signs of rust after the two weeks. The EvapoRust is the key. It's way too expensive for me to use it on everything though. The muriatic acid made quick work of the rusted fasteners and it removed any zinc that may still be there.

Thanks guys.

Water is what I've rinsed and what I've been doing wrong.

I'll switch to Laquer thinner to rinse after Evaporust.

I've got some Evaporust. It seems to be going higher all the time on price per Gallon I've noticed.