The best way to clean the contact lists and maintain email lists’ hygiene is by ensuring that the contact lists are free from inactive and stale contacts. Some of the ways to do so are as under:
Trace and delete bounced, inactive, and unsubscriber contacts.
Export the opened/clicked contacts. Then, delete the complete list to remove any inactive, erroneous email contacts. Then, reupload the exported list.
Properly segment the email lists as per different criteria. Remove the inactive contacts after that.