Safely cleaning vintage/antique metal jewelry? Also, adding tarnish and shining aluminum.

Factual Questions
1

I have a lot of old metal jewelry (no stones) that I would like to clean and am concerned about damaging them. What’s the safest way to clean aluminum, silver-plated bronze, bronze, brass, and copper jewelry (and others, but probably not gold or sterling silver)? A lot of the pieces benefit from being tarnished, so I don’t want to eliminate all of it.

Also, is there a way to add tarnish/other attractive discoloration to pieces? What metals does that work with?

Finally, a lot of my aluminum pieces have lost their shine. How can I restore it?

Thank you very much.

2

I’ve heard there is a special jewelry polishing cloth, called Sunshine polishing cloth. Jewelry stores might sell them, and I’m sure Amazon and other online stores sell them. Whatever you do, don’t rub the pieces too hard. I don’t know about aluminum.