Disinfect the iPhone leather case? How do they clean the demo unit at the store BEFORE each customer?

A good rule of thumb that I've found to work on Apple Watch bands, Leather cases, Silicone Cases, and other accessories is some soap and water is the best way to clean without damaging. Please keep in mind leather will eventually have a "wear" look.

Apple shows iPhone in stores without cases on them. So there would no reason to disinfect an Apple leather case in store because they aren't available to be held. You just choose one to purchase if you want one.

Shopping at an Apple Store in the age of Covid is quite different. You can't just walk into an Apple store and wait to find someone to help you. If you want to buy something, you either sign up outside the store, get your temperature taken and be placed in a line six feet away from other's in line. OR - You can and SHOULD make an appointment online to shop at Apple in an Apple store. You get to choose the date and time you want to shop and you show up and show an Apple employee outside the store you appointment confirmation, which is canned in and you are placed in line to wait for the sales associate to greet you. This saves significant time. Apple is very careful about letting people touch anything in store. And most items can be purchase without ever entering the store, including cases, phones, etc.

Hello swammic, there's many ways of cleaning your Apple devices and accessories.

How to clean Apple devices and accessories: https://support.apple.com/en-us/HT204172

Stay safe :)