[Speedslug]

Go as hot as you can with the water minimize the size of the setup if you can.

You can go to a smaller plastic bowl, a small sheet or two of aluminum foil and add the baking soda and the jewelry before pouring on the hot water.

Rumpling / scrunching the aluminum foil can give you more 'metal to metal' points of contact on larger things like flat wear or ear rings or other things that don't lay flat.

I have used this method for fine silver but I thought that sterling silver was made to not tarnish to begin with.
That's why I didn't think to suggest this method before.

You could use an aluminum foil pan to bring the water up to a good boil then add some scrunched foil to give you more metal to metal contact points.
Then put the jewelry in with tongs and add the baking soda.


Good Luck and let us know how well it works for you.