Reduce hum from an amplified acoustic guitar in a simple way

Hi
I think that everybody has noticed that you can reduce the hum from the guitar when you put a finger on a metallic part that is connected to the shield/ground of the cable.
On an electric you normally do that when you put a finger on a string.
But on an Acoustic guitar with built in pre-amp it is not that easy, you need to put a finger on connector itself.
I found out a way to connect my body to the cable shield and still have the hands free for playing.
I used a high ohmic ( 1 Megaohm) ESD wristband with a long cable and put the wristband to my foot ancle and connected the other end of the "ESD" cable to the guitar cable shield with a big "alligator clip" .
No more hum...
It may be awkward to do this on stage, but simple to do in your home "studio" during recording.