I am going to use vinegar to remove mill scale on a 12 ga mild steel project I am working on. Do I need to degrease the steel before submerging it in the vinegar? The first thing I did when I got the steel was to clean it with wd-40 and then coat it with gun oil (the silicin type) to prevent rusting. Will the vinegar naturally remove the oils, or should I use oven cleaner to prep the steel? Thanks for the help.
You'll need to clean it. Dish detergent will work fine, rinse it well and then let the parts soak over night. When they are nice and pickeled rinse them with water and dry them imediately or they'll rust slightly.
My own very recent and limited experience was that I didn't have to soak more than a couple hours, but I imagine any oil would work like a resist, and it won't get clean underneath.
