you can delete each arp entry manually with arp -d, a
simple way to clear a machine's entire ARP cache without rebooting, or deleting entries manually or waiting for timeouts is:
# ifconfig <hme0> <IP>
substitute your device and IP address, you can also change arp cache timeouts, eg: flushing the arp entries from the routing table after 1 minute:
#ndd -set /dev/ip ip_ire_flush_interval 60000
or discard ARP entries from ARP cache after 1 minute:
#ndd -set /dev/arp arp_cleanup_interval 60000
Hope it helps,
Carlos Almeida,