How do I clear the stored data once it's downloaded?

I've successfully downloaded the files but Jot still says I don't have any upload room. How do I clear the stored data once it's downloaded?

If you are sure about you downloaded your all data, including submissions, you can delete the submissions to open room for new uploads. This is the submissions page.You have 588 MB uploads. As a free account, you have 100 MB storage space. Please delete submissions until uploads reduce under 100 MB.