From brokenpoet.org wiki

Fu to remove all the odd text entries added by bfd

This will take out all the addresses in the deny_hosts file which are not real IPs.

sed -i '/\#/!s/.*[a-zA-Z].*//g' /etc/apf/deny_hosts.rules

The even better fu - developed later:

for ip in $(cat /etc/apf/deny_hosts.rules | awk '!/#/'| awk '/[a-zA-Z]/'); do apf -u $ip;done