aluminium cleaning

[Samir Shah <gofast1@home.com>]

As some of you may be aware, both bays of my garage are occupied by cars
with dismantled engine compartments - the 635 is getting a head gasket,
and the new Audi is getting all rubber in the engine compartment
replaced while being serviced/debugged.

So, while its all apart, I'd like to freshen up the aluminium parts -
intake manifolds, BMW head, valve cover, etc.

What products/chemicals have you guys/gals in the concours set found
that will brighten up the aluminium, without destroying all the rubber
in the vicinity? So far, I've tried cleaning with Simple Green, a wire
brush, brake cleaner, but no luck - the aluminium just does not sparkle!

All help appreciated. Thanks. Samir.