Hi Marie, here's a tutorial! https://bottomlineinc.com/life/cleaning/new-use-for-sour-milk-clean-tarnished-silver
Here you go, this should help!
The milk serves no purpose it's the acidic vinegar or lemon juice that cleans it...so just use the vinegar it's alot less messy and disgusting than curdled/sour milk. Mix warm water with vinegar (1 part vinegar to 3 parts water) and let the flatware soak for up to 30 minutes.
Dry flatware with a microfiber cloth.
Polishing with white toothpaste and wet cloth is best safest way to clean/polish anything silver without ruining it,use a small soft bottle brush, soft bristled toothbrushes,wood toothpicks to clean any intricate parts,then rinse under warm water, dry with microfiber cloths asap before any water spots get on it.
I agree with Lynn, the easiest way is to go with the plain old fashioned toothpaste with no get, peroxide, baking soda or whitener or anything to clean your silver. It is the safest and rinses off much easier than silver polish and does not remove a minute later of the silver when you do it.