According to Wikipedia, "UK advertisements are presented by "Barry Scott", an effusive character played by Neil Burgess, who claims that Cillit Bang can remove limescale, rust and ground-in dirt, and places a copper-plated One Penny coin in Cillit Bang to demonstrate the product's cleaning ability. In another version of the advert, Barry is joined by a stereotypical housewife character, Jill, who remarks of his penny-cleaning demonstration, "You love that one, Barry!".
(The back of the container originally listed copper as a substance on which one should not use Cillit Bang; however, it has since been amended.)
Haha!