Soda Blasting Electrical Parts-Fuse Block, etc.
Your results look great!
You can get coarse grade blasting soda from amazon.
I have used this type on some electrical connections inside an out. It is much faster than kitchen soda. I have also used it on other parts. It does cut faster so not as much time or pressure is needed on sensitive parts.
I like the soda b/c it is water soluble so you can spray the object with a bit of water to remove any soda residue if you want to. Supoosedly it leaves a bit of an anti-corrosion coating if you leave residue on although I would probably use something else for anti-corrosion long term.