I wrote a previous post on how to clean amber. A LOT of people have looked at it. I'm clearly not the only one who didn't know that amber can't get wet or the surface gets cloudy.
The best solution I could find was to soak the amber for 10 days in almond oil which restored the shine 95%. A certain Wendy commented that she'd used natural toothpaste to buff her ruined amber. Then she applied another light coat of toothpaste, let it dry, buffed it again. She used Kingfisher brand which I think is only available in the UK. I used The Green Beaver Company (Canada).
My ring is now 100%. Very happy. Thank you, Wendy!