Well I did an experiment yesterday evening. I had some paint mixing plastic cups..... I put some Limeaway in one cup and some muriatic acid in the other. I put one of the plates that I am wanting to work with in the limeaway and a piece of A36 roundbar in the acid. Small amounts of each. Since the mureatic acid requires more ventilation, it was placed outside where the temps were falling below zero for my test and the limeaway was inside the garage and covered.
I left both pieces to soak for 3 hours and then rinsed and scrubbed with a nylon/plastic parts brush. The Limeaway piece was completely stripped of the mill scale and the slag left over from the laser cut. The acid piece was spotty and will require more time or the use of an abrasive. I rinsed both pieces and sprayed them down with some Windex w/ ammonia, dried and coated with some of the WD-40 Dry Lube.
My conclusion is that the Limeaway does an excellent job when used at somewhat of a room temperature, and the acid is less effective when used outside in cold temperatures. I am assuming that warmer temps would probably help with the acid. Since I have quite a few pieces that I will be wanting to strip in the near future, neither of these processes will do what I need done. I wasn't able to try the vinegar because mamma didn't have enough in the kitchen for me to try.
So for occasional need for removing the scale, I recommend the Limeaway, based on the fact that it is easier/safer to work with and will remove any trace of mill scale and rust in just a short time..... depending on the size of work piece and is easily disposed of.
For my needs and the fact that I will likely be needing a repeat process on a bigger scale, I guess I am going to have to look more closely at the electrolysis method and spend some $$ to get set up.
Many thanks for the advice and information. You've been a big help.
Jim