Need to wipe a config from an interface a quick and simple way is to use the default command.
rtr#conf t rtr(config)#default interface GigabitEthernet0/0 Building configuration... Interface GigabitEthernet0/0 set to default configuration
Use sh run and this will remove all the configuration under this interface.
**note you do not have to go into the interface to clear the config from the interface.
