If you've collected personal data and you no longer need it, you should destroy these records.
◾ Paper records
If you keep paper records you could use a shredder or a shredding service. If you decide to take this route, make sure you’re satisfied they’re a reputable company that will destroy the documents securely.
◾ Delete digital information and any back-ups
Even if you have deleted files from computers and other devices, some systems will back up your information so there will still be a record.
To deal with this you could try:
• getting secure deletion software installed that will overwrite data one or more times; or,
• seeking specialist IT advice if you need it.
Secure deletion software is available from IT security firms. There are also other free software products which you can download and use, but make sure it comes from a reputable source and double-check any claims made by the company.
You need to be able delete data securely from a range of devices and types of media, and you may decide that a third party can do this securely on your behalf.
If you hire people in to help you with this, you will need to check their credentials and have a contract in place if you’re going to grant them access to the personal data you hold.
Source: ICO - We’ve got more information and practical examples for you to read here: https://ico.org.uk/for-organisations/sme-web-hub/whats-new/blogs/practical-methods-for-destroying-documents-that-are-no-longer-needed/