How do I unset an IP address set with ifconfig?

I recently used ifconfig en1 1.2.3.4 to set the IP address of a network interface (specifically, the wireless card) on a Mac… How can I remove/unset it?

Using the graphical network configuration tool doesn't seem to change (or even be aware of) this address - when I use it to manually set an address, a second address is added to the device.

For example, right now ifconfig shows:

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    ether 00:23:xx:xx:xx:xx 
    inet 192.168.141.99 netmask 0xffffff00 broadcast 192.168.141.255
    inet 192.168.1.112 netmask 0xffffff00 broadcast 192.168.1.255
    media: autoselect
    status: active

The first address - 141.99 - is the address I manually set. The second address — 1.112 — is the address assigned by my network's DHCP server.

Use delete:

ifconfig en1 delete 192.168.141.99

To clear all ip address associated with en1:

sudo ifconfig en1 0.0.0.0