How to keep this build up from happening?

I finally got the insurance on my mother’s old diamond and I have been wearing it. The man who did the appraisal cleaned ring for me beautifully. Now there’s a film on the back. I am not using products. I am however, washing my hands. I do not let lotion, touch it, etc. Why does this keep happening? I have an emerald and it takes months for it to get like this. I did see a product at Walmart or target for keeping rings clean but I’m not sure if that’s safe or not. In the last picture you can see the clouding though the ring. Any good tips ?💍 🥲🥲🥲Advice, please.