Started using Evapo Rust (or somesuch) it was available locally but it says non toxic so I didn't have too high of expectations. Rebuilding a set of calipers and they had some scale which I was at a loss of how to remove it all in the nooks and crannies- left them for 24hrs each, washed then hit with Picklex and VHT caliper paint- hope they last as good as they looked. Also had some rusty windshield wiper arms I was going to blast and they are looking good too out of the solution.