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