$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);

Raylight2:
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);

use mySQLI

Am a novice and i use cleanvalues... Am i safe?

you should upgrade to using mysqlite same as MYSQLI,
but if you insist, stripslashes and encode base64 are secured methods enough for database.

for passwords, Also use A SALT VALUE, attach it to the submitted data before been sent to the database.

Raylight2:
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);

1. Use prepared statements with PDO. takes care of query filtering
2. Encrypt your passwords with BCRYPT. its probably the safest, popular encryption algo out their. with it, there's no need for using a salt.

thank you all for your comments I'll apply them