Cisco IOS error: Static entry in use, cannot remove

This is a Cisco 2951 ISR running 15.0(1r)M16 (c2900-universalk9-mz.SPA.154-1.T.bin)

If a NAT entry is in use, you'll get an error:
router(config)# no ip nat inside source static tcp 192.168.30.5 80 interface GigabitEthernet0/1 12345
%Static entry in use, cannot remove

Clear the NAT translations first:
router(config)# do clear ip nat translation *

Then try again:
router(config)# ip nat inside source static tcp 192.168.30.5 80 interface GigabitEthernet0/1 12345
router(config)#