Crossposted and followups to alt.home.repair. This topic has been
discussed frequently there.

robert.e.king wrote:
I need a source for a duplex switch, 2x SPST, 120/240 Vac, 15Amp. Must
be rated COPAL or ALR/CU (for use with aluminum wire). Home centers
and internet sources I found carry only CU-rated duplex switches. Any
ideas?

Disclaimer: I am not an electrician.

A quick turn through the Leviton, Pass and Seymour/Legrand, and Hubbell
catalogs don't show anything suitable, which is a reasonable clue that
it may not exist. You might try a local electrical supply house - often
the name will be something like "Acme Electric Supply" - to see if they
have any ideas.

You might be able to install a wider box in the wall and use two single-
gang CO/ALR switches, which still seem to be obtainable. If you don't
want to cut into the wall, maybe you can use a wider surface-mounted box
over the existing hole. Wiremold is one manufacturer of boxes like this.

You could join some short copper wires to the existing aluminum wires
and use the widely-available copper-only wiring devices. There are
apparently two major ways to join copper to aluminum wire - one of them
has to be installed by an electrician, but is claimed to provide a much
better connection.

Disclaimer: I am not an electrician.

Matt Roberds