Small premise: skin type is different from person to person. Sometimes a particular acidity of the PH can accelerate the oxidation process: it is a natural, totally subjective process.
If you notice that your skin gets stained by wearing jewellery, it is not an allergy, just wash the affected area with soap and it will go away.
That said, here's how to take care of your jewelry:
First of all, protect them from humidity as much as possible
So when they are not used, it is better to store them safely in a small box or bag, separated by metals. An excellent solution is also to put anti-humidity bags with silica gel inside (which are usually found when buying shoes).
The latter will not allow condensation to form and therefore slow down the oxidation process.
Non-plated jewelery is not afraid of water
The materials used are: yellow bronze (copper and tin alloy), natural silver and gold so they can be worn even in the shower, nothing happens, indeed, every time they are soaped up, a thin patina is already removed, but I recommend drying them very well afterwards.
