Indeed. To be honest, Mick, I'm struggling to comprehend why anyone would use that stuff on their coins. It contains sulfamic acid and phosphoric acid.
I'd imagine it would do more than just get rid of the dirt.
Apparently, In August 2009, it was revealed that household cleaners such as Cillit Bang and Mr. Muscle have been used to clean plutonium stains at the defunct Dounreay nuclear power station in Caithness.