The acid etches the aluminum of the carb. Makes it pretty and shiny....however, it is also etching the small passages in the carb....Leave it long enough and you will have a clean looking lump of aluminum....
Disassembly and ultrasonic cleaning with a tiny bit of surfactant (dawn, palmolive, windex, fantastic) will actually clean the small passages and not remove any material.
If you are removing aluminum on the outside, you are removing aluminum on the inside.
Personally, I prefer a dirty working carb to a shiny non-working carb.
Soda blast the outside to make it pretty, ultrasonically clean the inside = best results.