Thanks to Aaron Jennings for the photos and report – that “ghost sign” is uncovered on a building undergoing renovations at 5001 Delridge Way SW [map]. King County Assessor records say the building dates back tp 1925. We haven’t found other history yet, but the sign clearly notes it was once home to William Damaske‘s drugstore.
You can find lots of online references to “ghost signs” around the city, like this site; seldom are they as clear, however, as this one! (Here’s a West Seattle example.) If we find out anything more about the Delridge sign, we’ll add to this story.