Good flag practices - energia msp430
I haven't worked with this processor yet but I am 100% sure there is some way to track the push button transition states

i.e un_pressed_button(low) - > pressed_button (high) transition
and the vice versa

If you do not want to use the flag you need to check for the 

pressed_button(high) -> un_pressed_button(low) transition on the push-button

sudo code would be like,

if(current_state_of_button == LOW &amp;&amp; previous_state_of_button == HIGH)
{
    clean_leds();
}


you will have to keep track of the states with two variables. OR setup two ISRS that fire on the two possible transitions. Hope this helps