[TheForge] iron or steel in brass keys

[Paul]

On 1/8/2010 5:12 AM, Jeff & Leslie wrote:
> lately I've noticed a few "brass" keys that are picked up by a strong
> magnet.  Is this common?  I've not been aware of it until recently.  I
> noticed it with a couple of magnets that are so strong they'll stick
> together with my hand in between and anytime someone is intrigued and starts
> playing with them a little blood ends up being shed when they slam together.
> I keep one on a vise in the shop and whenever I need it off its a battle.  I
> usually win though.
>
> Jeff in frigid tallahassee
>
>
>    
Haven't noticed but I will start looking... could be (from  WIKIPEDIA):

    * *Aich's alloy* typically contains 60.66% copper, 36.58% zinc,
      1.02% tin, and 1.74% iron. Designed for use in marine service
      owing to its corrosion resistance, hardness and toughness. A
      characteristic application is to the protection of ships' bottoms,
      but more modern methods of cathodic protection have rendered its
      use less common. Its appearance resembles that of gold.^[16]
      <http://en.wikipedia.org/wiki/Brass#cite_note-15>

don't know if that is enough iron to cause the attraction but it is a 
possibility. Might not be that alloy specifically  but a contaminated 
chinese brass alloy...
Paul in snowy waukesha