Example:

Delete all the addresses from the private network 10.0.0.0/8:

netadm@amber:~ # ip -s -s a f to 10/8
2: dummy    inet 10.7.7.7/16 brd 10.7.255.255 scope global dummy
3: eth0    inet 10.10.7.7/16 brd 10.10.255.255 scope global eth0
4: eth1    inet 10.8.7.7/16 brd 10.8.255.255 scope global eth1

*** Round 1, deleting 3 addresses ***
*** Flush is complete after 1 round ***
netadm@amber:~ #

Another instructive example is disabling IP on all the Ethernets:

netadm@amber:~ # ip -4 addr flush label "eth*"

And the last example shows how to flush all the IPv6 addresses acquired by the host from stateless address autoconfiguration after you enabled forwarding or disabled autoconfiguration.

netadm@amber:~ # ip -6 addr flush dynamic