128 votes51 comments · The new Outlook on the web (Office 365) » Mail · Flag idea as inappropriate… · Admin →
Hey, thanks for your feedback! This option will be added back to OWA in the next couple months. We’re working on improving the service that powers Clean Up, and then we’ll add this option back!
Here is the direct link that got me to the cleanup wizard.
This shouldn't be hidden away, it is incredibly useful.