On a new client’s server, I ran into an issue where a drive was running low on space and I found that another user account on the server (which had been deleted) had files in the Recycle Bin!
Thankfully, I found this Powershell command which worked to delete the files. All you have to do is open a Powershell console as admin and run the following command:
Get-ChildItem “C:`$Recycle.bin\” -Force | Remove-Item -Recurse -force
You can append -Whatif to do a test run and see what files will be deleted before actually deleting them.