Is it possible to delete old records from the admin panel? How?

You sure can!

When you login to the admin module via the web, click "View All Records" or just do a search for the record(s) you would like to delete. In your list of records, find the row for the item you want to delete and follow it all the way to the right side of your screen.

There you will see the option to edit or delete the record. If you have a lot of fields in your form, you may have to scroll to the right quite a bit.

Hope this helps!