For ages I've been trying to remove a particularly nasty residual glue, from the windscreens of the cars, left behind after taking out old insurance company holders.
If you have the same or similar problems then here's the answer. We were shopping in Lakeland the other day, Jan's favourite store, alongside Marks and Spencer, John Lewis and about 20 others, and she pointed out a product that she uses for similar jobs.
Sticky Stuff Remover Gel really works. It shifted glue that had hardened in the sun and had resisted all attempts to scrape it off. Good stuff.