WayneBR,
I removed the clip on my E1 by first taping around the clip with a couple of layers of masking tape (to protect the light's finish) and then used a bench grinder to grind off the head of the rivet. After I got the clip off, I used a Dremel tool and one of the rubber "polishing wheels" to take the sharp edge off of the rivet stud. I think it came out pretty good. Then I bought a KL1 head with no clip and left the old head in a drawer never to be used again!
Kirk