I dug my shed and found an unknown bar blown the powders.
Many white powders wrapped around the unknown.
The unknown is composed of a plastic part and blue something. The plastic part is combined with a flat metal part.
And it seems the metal part connects to a black wire.
The opposite side is like this,
There's a rust marked X on the metal.
I compare the unknown object with my AA alkaline battery. The metal part of the unknown is similar to minus poles of AA batteries.
But the hight of the unknown is taller than the AA battery. The white powder and the blue somehing might be alkaline electrolyte, dissolved the surface package and the film. Then, they might have got hard, I imagine.
Long time ago the unknown might be a AA battery "MARK X".