Guys there is a small workaround that seems to reduce the dropping of calls - acrylic nail varnish. I just applied several coats of acrylic resin on the rim of my iPhone and after letting it dry it seems to have reduced the number of bars that get dropped. I was getting almost zero bars after clenching with my left hand, but now I have a minimal of three bars at all times. It seems to work exactly like the tape method (creates a barrier between hand and the rim so no conductivity can take place) but is less intrusive and more durable. Hope this helps anyone with the problem. Marcus.