How can you make dull sterling silver shiny?

Answer 1

You can dissolve everything in concentrated nitric acid somehow (that will be quite slow and expensive). dilute everything as much as possible and use NaCL to extract AgCl.

collect and wash white precipitate to remove all soluble salts.

finally use drain cleaner or ammonia to dissolve that white insoluble salt, and add some glucose sugar.

black precipitate is very pure silver.

Cheaper method should be to use electrolysis but it requires some low voltage current source and container with electrodes. everything must be made in a way to electrically transfer silver from positive electrode onto negative where it will form black deposit.

any acid can be used as electrolyte.

Answer 2

Dip it in TarnX. You can get some at the grocery store