Since we have a new jailbreak out ios 9.2-9.3.3 from pangu team , you can now jailbreak your idevice using a windows computer or you can also just install the jailbreak app from panguteam and jailbreak without a computer. i will let here all files you need to remove icloud. we are talking about idevices iphone ipad or ipod 64bit for now . Pangu did not release yes a jailbreak for older devices 32bits. Also this method needs a ios compatible with jailbreak. the latest jailbreak is 9.3.3 from pangu.
DONWLOAD for iOS 9.2 9.3.3 (64-bit devices only) windows software
jailbreak without a computer use this link
Jailbreak 9.2 – 9.3.3 – onlinejailbreak.com IOS APP install from your idevice
You need jailbroken idevice
How Delete iCloud account Without Password
How to remove iCloud using iFile from Cydia ios 9.3.3
The steps are as following :
1 : Install iFile from Cydia
2 : Open iFile and go to : /var/mobile/library/accounts and Delete : Accounts3.sqlite, Accounts3.sqlite.shm, Accounts3.sqlite.wal
3 : Go to /var/mobile/library/ConfigurationProfiles and Delete : ClientTruth.plist and CloudConfigurationDetails.plist
4 : Reboot
5 : you will not have icloud id anymore , you must understand the icloud id will still be on apple servers but not on your iDevice anymore.
you can now add new icloud id and ready to go.