Will the inner zipper scratch the screen?

No, the zipper does not touch the screen at all. We designed the low-profile zipper to be sewn into the binding, and it tucks into the binding when folded. Although the zipper looks long, it does not crest over the edge of the injection-molded holder. It is completely unable to touch the screen.

Can the camera be used while in the case?

Yes, there is an opening for the camera and flash and neither is obstructed by the case. The hole was made to the exact recommendations by the phone manufactures. 

How hot or cold can it get with the case on it?

The Environmental Requirements provided from the manufacturer are 32° to 95° F (0° to 35° C). Our cases are designed with a “passive” (not battery powered) heating and cooling function. This generally allows users to extend these around + or - 15°- 20° in either direction for several hours. The numbers are relative to how long they are exposed and if the device is in use at the time. For instance, if the device is being used in a colder climate, the heat from the device will be reflected back toward itself by our cases and extend the time it can be exposed. A good example would be to think of our cases as a high tech jacket that someone wears to climb Mt. Everest...it will keep you toasty warm for a while but if you just sit there in it forever, you’ll eventually freeze. Conversely, in a hot climate think of it like a cold beverage sitting in the cooler in trunk of the car...it stays cool for a while but if you wait too long you're in hot water.

Is there any special way to keep the cases clean?

Anything you use on a daily basis is going to get dirty after a while. The good news is that Salt Cases are easy to clean with a simple facecloth and a small amount of soap. Just remove your device from the case, wet the rag with a dab of soap on it, and gently rub the dirt away, let dry and you’re all set!