Looked like silver but yeah, aluminum. I saw a picture where a guy poured melted aluminum into an ant hill and when it cooled brought it up and you could see all the galleries and tunnels they built.
That's one of my favorites to view on YouTube; beautiful artwork from pouring aluminum into ant hills. PETA doesn't like that. But pretty art created from nature. As for car bodywork, the tin alloy needs a higher temperature than lead to melt; old cars were easier to mate body parts as the lead melted at lower temps. When I was young I visited the Ford plant around Fremont and watched men slapping lead body filler on cars by hand. Stuff that is done by robots now.
Anyway, a shame to see all the cars, homes and businesses destroyed, perfectly good stuff lost by the residents. Everything they worked hard for is gone. Sad. Can't replace all the labor and love that went into their possessions, not to mention lost memories and keepsakes. Friend of mine lost everything in the San Bruno fire and is still trying to recover from it, years later.