I find Sierra and ElCapiton does not support Empty Trash securely and it is very possible that the Flash Drives do not support that either.

Click Finder on top then Preferences then Advanced.



Move to iOS from Andriod

“Move to iOS from AndroidDuring setup you can migrate your content automatically and securely from your Android phone.

Download the Move to iOS app. On your device running Android version 4.0 or later, see the Apple Support article Move from Android to iOS and download the Move to iOS app.

Move your data from Android during setup. When setting up iPad, on the Apps & Data screen, select Move Data from Android, turn on Wi-Fi on the Android device, open the Move to iOS app on the Android device, then follow the steps.

Note: You can use the Move to iOS app only when you first set up iPad. If you’ve already finished setup and want to use Move to iOS, you must erase your iOS device and start over or move your data manually. See the Apple Support article Move content manually from your Android device to your iOS device.”
Excerpt From: Apple Inc. “iPad User Guide for iOS 10.” Apple Inc., 2016. iBooks. 
This material may be protected by copyright.

Check out this book on the iBooks Store: https://itun.es/us/Cf0Odb.l