How to clear Memcache and redis without restarting the service

How to clear memcache and redis without restarting service.
Clear Memcache
telnet 172.25.16.191 11211 Trying 172.25.16.191... Connected to 172.25.16.191. Escape character is '^]'. flush_all OK quit Connection to localhost closed by foreign host.
Clear Redis Cache
[root@memcache ~]# redis-cli -h 172.25.16.191 172.25.16.191:6379 > flushall OK