Those ads show another side of the golden Hollywood era and its studio system. Stars were used to sell non-movie products, thus garnering simultaneously publicity for themselves and the products. This was encouraged by the studios, especially because normally the money which the companies had to pay for the participation of the stars went to the studios and not to the stars. How this financial aspect was handled in Irene's case, who started working free-lanced rather early in her career, is something I don't know.
Here are the ads which are decidedly "movie product related" - beautiful testimonies of bygone times.