Just do it. Go to your email’s inbox (or all of your various email inboxes) and start cleaning. Here is how to do it:
The short cut.
Archive the entire inbox. If you are brave delete the whole thing.
There should be a checkbox to select the entire listing.
Once you checked the box press the archive icon.
The system may ask you if you want to archive all the messages in your inbox or just the ones in the current view. Choose to archive all the messages in your inbox. And again, if you are brave, delete them all.
In the case of deleting, anything important will come back around. In the case of archiving, you can search for items that you need if they come to mind.
The long way around (give yourself a few hours to do this).
Go to the oldest email in your inbox and work up the list.
Delete what you do not want to keep.
Archive emails you want to keep.
Print important information and then delete it or archive it.
Respond to emails that you think you should respond to no matter how old they are.
Unsubscribe to anything that you did not originally open or no longer care about. Each time you unsubscribe search for that sender and delete all of their emails to you. Odds are there are a large number of emails from each sender.
Keep it out zero. Empty your email inbox every day or when you open it. It may seem to be hard at first but it will give you freedom from email inbox clutter. And unsubscribe to any new email that comes that you are not truly interested in.
See if you can apply this same approach to other areas in your life.