In my haste to get the job done I forgot to wash off the wallpaper paste left after removal of a vinyl border below the coving. I have only given the wall one thinnned coat of white Dulux Matt. Can I go over this with Zinnser Gardz and continue painting, or should I rub off the paint, apply Gardz and re-paint? I can clearly see the line where the border paper was although there appeared to be very little paste residue after stripping.