You can't remove these commands, you have to basically reset them back to original or different:
aaa authentication telnet login local
aaa authentication ssh login local
would reset them back to original state.
Below is the basics of the overall command 'aaa authentication':
aaa authentication <access method [console, telnet, ssh, web]> <login or enable> <primary auth [local, radius, tacacs]> <sec auth [none, local, radius, tacacs]>
hth...Jeff