Painting - vinyl wallpaper

My sister and her husband have just purchased a home that is twenty+ years old. We think that the walls have never been cleaned, and they have a heavy cigarette smoke stain on them. We have tried all kinds of cleaning supplies on the vinyl wallpaper in the kitchen. It is lighter than before, but there is still white spots where the pictures were on the walls. Can you please give us a suggestion on how to remove this? Thank you

That sort of color change of a material where exposed to the sun, heat, and grime is part of the landscape now. It happens with wooden walls, the pictures keep the wood from getting darker. Short of replacing the wall paper, you probably have few choices for blending the spots from the pictures.

Hope this helps.