Gold ink on wallpaper persists...

In my bathroom when we moved in - 30 years ago - there was a black marble-effect wallpaper with gold "grouting" printed on it.

We still - despite having stripped and painted the walls (where I haven't tiled them) - can see those lines where the gold lines were on the wallpaper.

Any suggestions to finally get rid of them gratefully received. Also, why is the gold so persistent?

TIA,

NMG

Its not gold..its normally Brozining powder, the stains you see are probably from corrosion caused by the moisture in the room

Give the wall a coat of alkali resisting primer sealer