$limit = (Get-Date).AddDays(-7)
$path = 'C' + ':\$Recycle.Bin'
# Delete files older than the $limit.
Get-ChildItem -Path $path -Recurse -Force | Where-Object { !$_.PSIsContainer -and $_.CreationTime -lt $limit } | Remove-Item -Force

# Delete any empty directories left behind after deleting the old files.
Get-ChildItem -Path $path -Recurse -Force | Where-Object { $_.PSIsContainer -and (Get-ChildItem -Path $_.FullName -Recurse -Force | Where-Object { !$_.PSIsContainer }) -eq $null } | Remove-Item -Force -Recurse