Backing up WhatsApp chats
Firstly, to update your local chat backup :
Settings -> Chat backup -> Backup

Now, take a copy of WhatsApp folder somewhere. This will copy all your whatsapp related data - chat backups, media etc. In case you want to backup &amp; restore only your chat backup, copy msgstore.db.crypt12 from Whatsapp -> Databases folder.

Then, uninstall WhatsApp app and delete WhatsApp folder, i.e, "clean my WhatsApp completely"

Finally, copy WhatsApp folder back to phone storage (in case you only copied msgstore.db.crypt12, make Whatsapp -> Databases folders manually) then install WhatsApp app. In the setup it will say `Backup found,do you want to restore' : select yes.