Tarnishing of silver, which is typically a blue/purple/black colour, is triggered by its reaction with elements such as sulphur, moisture, oxygen and chlorides.
Oxygen and Sulphur compounds in the atmosphere, such as sulphur dioxide, hydrogen sulphide gases and organic vapours, all contribute to the tarnishing process, which is also accelerated by other factors.
Apart from the sort of aging that Judd considered acceptable, like the tarnishing
of a copper surface, problems such as those investigated by Nagy are manifold.
"It is the people who are doing the accusing who are dragging football down and tarnishing
Houston said: "Once again, Edwards seems to be tarnishing
Manchester United's great reputation.
English football hooligans who caused mayhem in Madrid before Aston Villa's UEFA Cup quarter final last night were condemned for tarnishing
the club's name.
"In terms of tarnishing
my career, I said it before, I'm doing this for me," Phelps said when asked if he fears his return might tarnish the remarkable achievements so far.
27 (ANI): Blaming India for tarnishing
Pakistan's international image, the Lahore Chamber of Commerce and Industry (LCCI) has suspended the sending of all trade delegations to India till bilateral talks between the two countries resume.
Saad Eddin Ibrahim, a 63-year-old sociology professor at the American University in Cairo who holds dual US and Egyptian citizenship, is convicted a second time of tarnishing
the country's image and other charges and is sentenced to 7 years in prison.
Defies Hollywood convention by playing gay often--and passionately--without tarnishing
his matinee idol image
The Oscar-winning filmmaker had sued clothing firm American Apparel for 6.7 million pounds last year for using his likeness on billboards without his consent, and tarnishing
He also asserted that his organisation is also planning to hold a conference of Islamic scholars to discuss the further strategy so as to prevent some people from tarnishing
the image of Islam.