Google Drive: Set Automatic Expiration Dates for Shared Files & Folders

This script is awesome for teachers or anyone who doesn't want to share files or folders forever. This will work for both publicly or privately shared items. 

Here's the guide from Digital Inspiration:

The script will run at the specific time and remove all the sharing permissions from your file or folder making them private and the shared links would no longer work. Here’s how you can use the script.

1. Click here to make a copy of the Google Script into your Google Drive.
2. Add the URL (link) of your shared Google Drive folder or any file hosted on Google Drive in Line #3 and put expiration date in Line #7 (remember to use the YYYY-MM-DD HH:MM format).
3. Open the File menu, choose Project Properties and select your Timezone from the dropdown. The date and time that you set in the script will use this timezone.
4. Go to the Run menu, choose Start and authorize the auto-expiry script to run at the specified time. This is open-source Google Script and none of your data is shared with anyone.

That’s it. You can close the Google Script editor window and it will automatically disable the sharing options for the specified file or Drive folder at the specified date and time. You can even specify sub-folders that are anywhere in the Drive Tree.

http://www.labnol.org/internet/auto-expire-google-drive-links/27509/