Well...I thought I might add one more point I just learned. My 1903a3 barreled action came back today from a parkerizing job. I had all my parts ready to go for assembly tonight, and I fit the stock before sending the action out. When I blued the parts a month ago, I boiled the cocking piece bolt collar, striker, and the little sleeve behind the striker. I don't like to have too many parts going all at once, so I did 8 iterations on these, and left them submerged in container of WD-40 while I did the safety lever, magazine cutoff, trigger, sear, and the floor plate from the milled bottom metal I was going to use. My water in the pot had gone down, so I put the steamer basket in and steamed this second round. They turned out fine, and I submerged them in the wd-40 and left it all there overnight. Next morning I wiped all the excess off the parts, and set them off to the side in a plastic container to wait on the action to come back.

Well, there were noticeable blotches of surface rust on the floor plate, trigger, safety lever, and magazine cutoff, and none on any of the parts that were boiled. Lesson learned, steaming requires a final rinse or a boil to neutralize any residue left on the metal after the last iteration. The rust was very fine, and carded off with oil and steel wool without a trace left behind.

I had forgotten I was still working on removing the pitting and sanding the trigger gaurd and so it is still in the white. When I blue it this weekend, I'll give all the parts a final boil in clean distilled water + baking soda to be safe.