Mark All Email in Mailbox As Read

I have an Outlook mailbox as follows:

Using PowerShell, how do I recurse through each folder (and its subfolders) and mark every message as read? (5_Misc is actually my "inbox"; I renamed it using MFCMAPI).


I've tried several scripts, but each one errors.  I can post them if it helps, but if there's a standard way to do it that'd be great.

Thanks for any help.