I assume you're concerned about documents being left on the print spooler? Are you bringing your own device or using one of the computers provided there? Some printers will actually save a history of documents which have been printed to that printer so you may need to delete them from the printer itself as well.
Please also note, that Windows 7 support ended in 2020 and therefore any security vulnerabilities within the past 3 years have not and will never be patched. Additionally, Firefox and Chrome are ending support for Windows 7 this year so you may eventually that many websites will stop working correctly.