Quickest way to transfer "on my mac" emails to "iCloud"
Is there a quicker way to move "on my mac" emails to "iCloud" that maybe doesn't involve dragging folders in the mail app? I have a LOT of emails I am trying to transfer and it's taking forever using the drag and drop method (not to mention I'm getting periodic error messages). Can I perhaps move the "on my mac" folder to "iCloud" another way?
Mac mini, OS X Yosemite (10.10.2), null