I tried to remove corrosion on an LRBC* by heating it, then dropping into cold water.
I reasoned that differential expansion and contraction of the good metal under the surface corrosion salts would result in the corrosion salts falling off the coin, or at least would be much easier to remove.
I was wrong.
Complete loss of the coin, into hundreds of tiny black particles was the result.

* Late Roman Bronze Coin.
Value loss? - about $15.