What? brownells steel white

[ssgross]

Opens the pores in the material.

yes. surface area is the key when rust bluing. evaporust or the steel white will leave the surface glassy smooth, sans any pitting underneath.

However, I just noticed baker is prepping an aluminum receiver. I don't think either product will work at removing corrosion from aluminum, nor any anodizing - even if it says it won't attack aluminum, the chelating agent only reacts with iron oxide.
For bare aluminum with corrosion - like spots of my Glenfield 70 I painted, paper polish is the trick. The old paint came off with orange stripper and mineral spirits. If you need to remove any anodizing - a sand blast with correct media is the only real way to go. A quick google showed dozens of threads on ar15.com of people unsuccessfull or mediocre results at best with chemically removing anodizing.