Answer: Both are chemical changes
Step-by-step explanation:
Tarnish can be defined as the product of the chemical reaction that occurs between a metal and a no-metal. The metal which is exposed to the moisture or get oxidized develop a thin layer called tarnish. Copper, silver, brass, magnesium and other metals get tarnished.
The polish removes the chemical product of tarnishing and keeps the silver in silver spoon intact. This involves the chemical reaction.
Salt and vinegar are the ingredients of the chemical formulation which can remove the chemical product of the tarnishing from penny. This involves the chemical reaction.
Both polish and silver and vinegar can bring a chemical changes in the metal without introducing the physical change as they do not affect the physical structure of the metal.