Today I noticed some tarnish in my H2O locket, so I took 5 minutes to clean it. Afterwards I thought maybe you do not know how to keep clean your silver, so here is a bit of help.
The product that I use is called Sidol Aladdin. I use it because my trusted jeweler recommended me to do so - I do trust him because my mom has been his customer for years, and they have built a good professional relationship.
This is what the product looks like:
It is also called "Magic Cotton", because the product itself is a pink cotton that is soaked in the cleaning solution. You take a piece and rub it onto your silver. You know it's working because it changes color to black. Then you buff it up with a soft clean cloth, and the piece looks like new.
I do not know if this is available out of Spain; when I lived in the US I used Wright's Anti Tarnish Silver Polish:
This one is a white liquid paste that you rub with a cloth onto your silver or silver plated object, and buff with a soft clean cloth. Then you rinse it with water and dry it.
Be sure to wear gloves (not made of rubber!) when using these products, because they are a bit abrasive. I also found you a guide to clean silver by the Bishop Museum.
Hope this helps you taking care of your silver!