How I can delete old submissions?

We use the form for a scholarship app.  I tweaked the 2015 form in just a few places and sent out the link.  When I go to the list of all the forms received, it has last years listed as well.  I only want to see submission from 2016.

You can filter the submissions data shown on the data grid base on specific date range.

Here's how:

You can then delete the data afterwards. You can select all the data (shift + select) to delete them all at once or delete them one by one.

Example:

You can also use this app to delete submissions http://apps.jotform.com/app/search_and_delete.