Remove flux stain from brass?

So - I fluxed my brass so i could see when it was annealed. Ended up pink where the flux had been. Went online (should have come her first). Tried white vinegar & peroxide - added to the problem. Then tried super pickle - it did something - but not enough - still can’t remove it with sandpaper. What about Brasso? Any other suggestions?
Thanks in advance,

I have always used “Super Pickle”. 50/50 Sparex dissolved in hot water and hydrogen peroxide. It’s important that the solution is warm and that you use fresh peroxide because it does go bad with age. Do not reuse the solution as it gets weak pretty quickly. It may take a couple of tries. Also don’t go by flux to see if brass is at anneal temp. Turn off the lights in your studio and wait for the brass has a pink glow.
Good luck with your project.

Thanks Jo - I did try super pickle, but will go out today & get new, fresh peroxide.

Jo’s recipe works for me when I make heavy brass bracelets with as many as 30 tiny solder points and lots of small areas for this satin to grow in, but not be accessible to sand or polish. I use a graduated cylinder to contain the super pickle as the bracelets are straight at this point having yet to be bent into a cuff shape. It does take fresh H2O2 and pH down and a lot of time. Heating also seems to help…Rob