[alt-photo] Clearing PtPd mouned on aluminum?

[Denny]

If you're clearing PtPd prints mounted on aluminum (as for example, the
process used at least occasionally by Irving Penn), what's the best way to
clear the prints?  I'm guessing that the aluminum would interfere with the
clearing, with a large excess of aluminum competing with the iron.  HCl or
EDTA might not be effective ( or might even be dangerous, liberating
hydrogen gas).   Am I over-thinking this?  
Thanks,
Denny