Aaron Fude wrote:
....

This is the inside of a very large old brass Russian samovar ...

What you see is a very thick layer of minerals, possibly 100 years
old. How does one go about removing it?
....

Start by soaking in hot vinegar...also could try the CLR lime removal
product which might be a little faster. After that, need more
aggressive acids, but w/o knowing the underlying metal better, caution
is the better course.

Time and these will _eventually_ dissolve the mineral solids...

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