Self-hosting an Infisical, a powerful open-source secrets manager, can be used to protect backup credentials and keep backups safe from malware. The process involves deploying Infisical with Docker Compose on an Ubuntu server, setting up a valid environment file, and configuring the Nginx configuration files. Once set up, users can log into the Infisical CLI and use the `infisical run` command to access their B2 application key and inject secrets just-in-time. This allows users to protect their backup keys while still being able to use them on other machines. The setup is easy, repeatable, and secure, making it a valuable tool for individuals who want to manage their secrets securely.