Reset codes and service menus

Reset Codes
Samsung: *2767*3855#

Nokia: *#7780# OR *#7370#

Most Androids: Hold down volume and home during start up then follow instructions

Default Passwords
Nokia: 12345

LG: 0000

Service Menus
Sony Ericsson: >*<<*<*

HTC: *#*#3424#*#*

Lumia: ##634#

Samsung: *#0*#