Clean up redundant messages in a conversation

You can clean up a single conversation, all the conversations in a folder, or all the conversations in a folder and its subfolders:

1. Select the email conversation you want to clean up.

2. On the Home tab, in the Delete group, select   Clean Up, then select the option you want.

   Or just use a button below:

   If you don't see the Clean up option on the ribbon: On the Home tab, click the arrow next to  Delete, then select a Clean up... option.