How to clean oddly staind 14K chain?

Long story short: chain came with darkened areas near back (not symmetrical to each side) that did not clean with : rouge cloth, ammonia (hey, several sites said it was good to use on gold), toothpaste, baking soda, Dawn liquid. No real change. Got professional jeweler electrosonic cleaning, some improvement. Someone suggested Mr. Clean w/o ammonia. Haven't tried it yet as don't want to open bottle unless I get some confirmation.

The jeweler who cleaned it thought there may have been heat/work done on some spots which may have been contaminated by a surface substance/chemical/cologne.
Center strand is mostly darker as well as center area of lower strand.
Any ideas I haven't tried?
And, what is the link style? I haven't found it on the chain supplier sites I searched.
Thanks!

 

https://www.antiquers.com/threads/how-to-clean-oddly-stained-14k-gold-chain.78251/

is there a good reason that you posted this twice.....

was the post it note idea not helpful?????

 

My apologies. As I got only the sunshine cloth idea on how to clean I forgot I had posted. I will asked to have it removed.