When you take it down to its component parts, an alternator is pot-metal
or steel (the shell) some more steel (the shaft) soft iron (the core of
the rotor and the cores of the stator coils) and copper (the windings,
of course) plus the bearings (probably either steel ball or roller
bearings, maybe brass bushings) and an insignificant amount of whatever
they used to make the type of diodes in it wrapped in either
high-temperature plastic or ceramic, a couple of chunks of carbon (the
brushes) possibly a bit more miscellaneous plastic for bearing seals,
and some sort of epoxy, plastic, or enamel coating on the copper wire of
the windings.

In other words, it's essentially inert scrap metal that nobody but the
most totally anal tree-hugger type is going to think twice about if it
goes into the normal trash stream. Nothing hazardous (or at least,
nothing in any meaningful amount, and what little there is is almost
certainly encased in a hunk of either ceramic or plastic that's likely
to outlast the human race unless deliberately broken open) involved to
require "special handling".

HOWEVER...
You *MIGHT* be able to get somebody that does alternator rebuilding to
give you a few bucks for it as a core. (but don't expect much more than
5-10 dollars, if that, unless it's some incredibly rare type)

Or, more likely, you can pay a rebuild shop (local or "mail-it-off" -
your option) to repair it for you, and have a spare on hand if/when the
one that replaced it takes a dump on you - chances are high that the
reason it died to begin with was nothing more than the diode trio,
brushes, or bearings giving up the ghost - All pretty trivial to fix -
*IF* you've got the gear, replacement parts, and mechanical/electronic  
know-how to do the deed yourself, and definitely trivial for an actual
rebuild shop.

That's a useful core... I'm surprised you didn't have to turn it in when
you bought whatever you replaced it with.  I'd either a) hold on to it
or b) give it to your local alternator shop - they might be able to do
something with it, whereas if you threw it in the trash it'd just be
thrown in the landfill.  There's nothing hazardous in it by the way.

Heck, if it's either a) an old '60s Prestolite or b) a Delco 10SI or
12SI and you're close to me, I might just offer to swing by and take it
off your hands!

nate

(chea^H^H^H^Hfrugal bastard)

Take the old alternator down to the local auto parts store. They'll
take it... they will have it re-built.

Professor
www.telstar-electronics.com