boiled potato maked metal shiny

[ssas]

could anyone explain why the metal rubbed by boiled potato, and not a raw one, could become shiny.
What kind of acid or chemical substances are responsible for this?
thank you

[alivingthing]

hot potato
马铃薯在烹饪过程中维生素C丢失

[Linn]

Here is another thing I have never heard of.
Perhaps it is the high starch content.

An other old folk remedy I have heard of is using a lightly bolied potato as a salve for inflamation and pain. Tried by friend of mine with terminal cancer and said it worked.

[victor]

I think, because of it's the boiled one (have much heat), the starch content in the potato will get reacted with the metal oxide which surrounds the whole metal thus makes the metal looks a little bit dark...
With the removal of this metal oxide layer, you'll obtain a metal without its impurities..

Um, just try it to Aluminium and Magnesium metal (because both oxide layers can be seen as a really black layer).....