Privileged EXEC mode
If the interface parameter is not specified, spanning-tree counters are cleared for all interfaces.
To clear spanning-tree counters for all interfaces:
device# clear spanning-tree counter
To clear spanning-tree counters for an Ethernet interface:
device# clear spanning-tree counter interface ethernet 0/1
To clear spanning-tree counters for port-channel 23:
device# clear spanning-tree counter interface port-channel 23