It should not need to be stated but you should have your favorite console cable handy for this.
These commands are used to reset your ASA back to factory default settings.
ciscoasa(config)# config factory-default
Based on the management IP address and mask, the DHCP address
pool size is reduced to 253 from the platform limit 256
WARNING: The boot system configuration will be cleared.
The first image found in disk0:/ will be used to boot the
system on the next reload.
Verify there is a valid image on disk0:/ or the system will
not boot.
Begin to apply factory-default configuration:
Clear all configuration
WARNING: DHCPD bindings cleared on interface 'management', address pool removed
Executing command: interface management0/0
Executing command: nameif management
INFO: Security level for "management" set to 0 by default.
Executing command: ip address 192.168.1.1 255.255.255.0
Executing command: security-level 100
Executing command: no shutdown
Executing command: exit
Executing command: http server enable
Executing command: http 192.168.1.0 255.255.255.0 management
Executing command: dhcpd address 192.168.1.2-192.168.1.254 management
Executing command: dhcpd enable management
Executing command: logging asdm informational
Factory-default configuration is completed
ciscoasa(config)#And now to save this.
ciscoasa(config)# reload save-config noconfirm
Cryptochecksum: 76d583b6 9edc66f8 a28d3ca7 d6642535
2620 bytes copied in 3.320 secs (873 bytes/sec)
ciscoasa(config)#
***
*** --- START GRACEFUL SHUTDOWN ---
Shutting down isakmp
Shutting down webvpn
Shutting down License Controller
Shutting down File system
***
*** --- SHUTDOWN NOW ---
Process shutdown finished