This tip comes from reader Julie.
I've field tested this on sugar spoons, a porringer, and a baby cup, all tarnished beyond recognition. I think every Church Lady worth her salt has opened a drawer in a sacristy and made a Horrible Discovery - something beautiful and abandoned to tarnish into dust. This will make those things polishable in fairly short order.
My whole family is trying this - as a chemistry teacher (by day... Church Lady by night!), I felt compelled to lead the way!