Stop in for a cup of coffee

Hmmm, yeh I think it was.
That makes sense. Then the answer to prevent the flash rust is to neutralize the acetic acid (vinegar) with baking soda before removing the metal from the solution and then quickly rinse using clean water and dry the part.

The oxidation is occurring because of the sudden contact with oxygen while the surface of the metal still has acetic acid droplets on it.