Without knowing what tools and equipment are available for your use, the easy method is to
throw it away and
buy another.
Do you have basic hand tools? a hammer? rubber bands? a freezer?, boiling water? a garlic press? a fork?, newspaper?
a)Using two forks, insert tine from fork one into air hole on 510 base, insert tine of fork two into wicking hole of coil head; unscrew the coil head anti-clockwise.
b)Pop unit into freezer or boiling water to attempt to loosen the threaded connection.
c)Smash top of coil head with hammer for more surface area, trap smashed part in a drawer or door and unscrew the 510 base.
Hope you get it sorted!
Cheers
I