I posted here (in 2009!) about a rusted chromed Raleigh International. I don't remember details now, but I used the very weak oxalic acid method. Something like a few tablespoons in 3+ gallons of water? Soaked for hours. Nothing seems to happen at first, just wait a bit.
The whole thread is useful.

I couldn't fit the whole frame in the plastic box, but the rust was at the headset and rear dropouts. So those got treated separately.

At that weak concentration, I didn't take many precautions. No fumes, no adverse skin effects (but I quickly rinsed my hands if they got solution on them.)

It's quite amazing how the rust disappears. But a few years later, with the bike in storage inside my house, rust was reappearing. I didn't do anything to seal the spots where the rust was.

before






After