PS command to delete unread email

Greetings,

Is there a PowerShell command, or other method that would allow me to delete all unread messages from all mailboxes for a defined period of time?  We give every employee a company email address, some of those employees hardly ever check their email, but the emails keep piling up taking up precious space.

I would like to be able to do some cleanup from the first quarter of this year and delete all unread messages as well as delete all items from their deleted items folder for the same period.

I just don't know the best way to do it.

Any help would be greatly appreciated.

ST