i used noise reduction effect from computer,
is there any such effect so that i can use even in stage
a noise gate is probably going to give you the best result for a high gain setup. adjusted properly, it will mute the signal to your amp when you are not playing. there also are FX that will specifically cancel hum. search electronic hum cancellation for guitar and similar.
-=tension & release=-
I have a BOSS one, ns-2 I think.... It works very well.