I was looking up info for both copper and brass cleaning again after dinner. I don't know about the silicone packet. Maybe try and see??? I'm thinking if we keep them clean with Brasso or Wright's Copper Cream that should do it.
If you are ever looking for long term storage there are jewelers packets that will keep them from tarnishing for up to 12 months. Bags:
Search
This article has good cleaning tips from a jewelers perspective:
https://www.riogrande.com/article?name=PreventingTarnish
An architectural digest article basically says to use Brasso or other similar cleaners.
How to Clean Brass Like a Pro
I seem to recall
@Skunk! mentioned Bar Keepers Friend in a thread some time ago but I don't remember the thread or context.