Mel Rees, Larry McGettigan, Jack Harrop, Ron Wigg are all post War II players for Watford. What do they have in common?
Is this anything to do with her taking part in an aggressive marketing campaign relating to Pepsi's taking over of Quaker Oats ? (George Fox would have been turning in his grave !)
No, much more straight forward than that, in a crossword sense. William Penn, the Quaker that founded Pennsylvania, was born in what used to be Woolworths in Rickmansworth. That has nothing to do with the answer.
Sticks to almost anything, cured by exposure to air, flexible rather than rigid when cured, soft but grippy, stable at either high or low temperatures, waterproof - what is it?