[fields 100]

There is one big rectangle can (with 4 capacitors inside) on my 16B tombstone, located in the rear middle. Does anyone know the correct original finish (color) of it? I thought it was galvanized, but there is some sort of different plating on the top of it.

[Mondial]

It was tin plated, like the tube shields.

[morzh]

It looks like tin to me.
Same material they used for roofs, tinned steel sheets. Or for canned food.

[GarySP]

Try using some Simichrome and a cloth buffing wheel on it. Should come back to almost original condition unless it was really wasted to begin with. If it doesn't, you're only out a little buffing compound and time. Take care, Gary.

[fields 100]

There are traces of tin on it. Under it some grey plating.When I buff with a wheel it becomes too shiny and unprotected corrosion wise. So I will probably go with steel wheel chrome spray, see how it looks like. The inside though is definitely tin, like a can of sardines.

[morzh]

I suspect they did start fro using empty sardine, or rather SPAM, cans

[fields 100]

Judging by the gauge, it is quite possible.

[codefox1]

I assume you are going to stuff it with younger Sardines. Unless pitted from internal or external bothers, should shine up just fine as already suggested. I've used pumice and little oil to do this, but!! goodbye decals and ink stamps if any.

Whatver you do, the result should match the rest of the set's overall impression and appearance to look as "original" as intended. Anything can be done with enough time and money.