I used this right away after I got my package from Thomann. It was magic on my silver mouthpieces. All of the ugly ducks turned to beautiful white ducks. It's easy to use only if you understood the instructions. It's a good product and a good deal for the money. I will buy it again next time.
Pros
Easy to use, don't forget to use medical gloves while working on this thing. It does the job well. My trumpet mouthpieces are like brand new mouthpieces again.
Cons
There are no English instructions. It would be better if there was a pdf instruction in English. Anyways, we asked for help from my sister in law who is in Germany. After that we understood the instructions written.
This might help you - INSTRUCTIONS
Important: Use medical gloves
1. Make the sponge wet, apply a little bit of the silver care polish on the mouthpiece. Make sure that the water is warm, not hot, not cold.
2. Using the wet sponge, apply the silver care on the mouthpiece and clean it.
3. Apply more silver care polish if it's necessary.
4. Once your done, clean it with warm water.
5. Finally, using a dry, clean, soft cloth, dry the mouthpiece. Keep rubbing the mouthpiece till it gets dry and shiny.
6. Do the same procedure to your other mouthpieces.