It’s normal for the sensor and sticker to appear as if they’ve been wet and have white salt deposits due to the solutions used during testing and shipping. This does not mean the product has been used.
Here's an example of a wet cap sticker:
Here's an example of salt deposits:
Again, these are not signs of a used sensor. Each sensor is tested in our factory and the testing and storage solution sometimes leaks out of the cap due to air pressure changes.