Silver cleaning method.?

It does... But over such a long timescale as to be negligible!

I use this method all the time and would recommend it.

1x tsp bicarbonate of soda

1/2 - 1 tsp salt

It does the same job and is gentler.

Not sure if it's the same thing, but I clean all my silver using soda crystals, but just warm (not boiling) water. It is actually less harmful to the silver than many of the silver cleaning solutions you can buy (so I was told by a jeweller). My brother works in the mess in the army and he says they clean all their silverware the same way so he showed me how. You put the tin foil into a container, add a little of the soda crystals and some warm water and put the silver in for a few minutes. After a minute or two, take the silver out, rinse under clean water and buff up with a polishing cloth. It looks great!