Hello @elliot_6557,
We are sorry that the answer was unclear from my colleague. I believe she should have added this: There is no way to clear out preview files, proxies, and cache files within the app. You must delete the app and reinstall it.
As a fellow Rush user, I feel that this feature is really needed, especially since the removal of Creative Cloud Sync. On behalf of Adobe, I apologize that this feature is not yet available.
If you have projects that you need to export and are running out of space, the only option is to move the project to Premiere Pro. If you do not have access to the app, you can install a seven day trial to finish off and output your project.
As we support reps we constantly provide feedback, bugs, and feature requests from this user-to-user forum, so they are aware of this shortcoming.
If you are using iOS, I invite you to try Project Violet, where new features are being added to a newer mobile video app.
Sorry for the frustration.
Thanks,
Kevin