How do I "empty the recycling bin" in Teams? Out of disk space error

Tackleberry Technically, there's no "Recycle Bin" in Teams. Teams generally makes use of two places where files can be stored by default: SharePoint Online or OneDrive. When you look at the Files app, the 'Microsoft Teams' view generally contains files that are stored in SharePoint Online and linked to a team. What's under 'Downloads' are files that you downloaded to your local device from a team or a chat. Whatever is under 'OneDrive' is basically a view of what's in your OneDrive.

When you delete a file under the 'OneDrive' view, it will be removed from your online OneDrive, which will then eventually sync this with the OneDrive app installed on your device. The file is immediately deleted from your local device, and stored in the online recycle bin. You can find this recycle bin by going to the Office Portal, click on the OneDrive icon on the left, which will open your online version of OneDrive, where you'll find the Recycle Bin option:

You can restore/delete files from the recycle bin. Files stored in the recycle bin should not count towards your storage limit.

If it is indeed OneDrive that's out of storage, I would recommend going to the online OneDrive website, click on the 'cog icon' at the top to go into the OneDrive settings, there should be an option for 'Storage Metrics'. This should tell you how much is really in use and where.