Stripping brass finish off

[Moyboy]

I think it refers to the 'bleacher' models where it removes the plating from plastic parts not the older metal parts. Electrolysis may be the way to try.

[Diecastmolester]

The bleach is caustic. It eats away the only a few molecules thick layer.

Hmmm...brass is zinc and copper. Looking on the Internet, mazak/zamak appears to be mainly zinc, plus aluminium, and copper (and some sources say it also contains magnesium, hence the 'm' in the name.)
I don't see why the bleach (NaOCl) should stop at the brass, especially since zinc (the main component of mazac/zamac) reacts with alkalis.

I'm not a chemist. All I know is it works a treat for me.

[Idris]

I think it refers to the 'bleacher' models where it removes the plating from plastic parts not the older metal parts. Electrolysis may be the way to try.

You may well be right. (I was going by the topic title.) However, that is also an interesting process for which I have also been unable to come up with a satisfactory explanation.