I think the many approaches taken to solving Superman's Kryptonite problem grab the wrong end of the stick.
If Dr. Klein or someone could just make a spray that would make normal Earthers react to Kryptonite as Superman does it would go a long way to solving his problem.
Keep a few pellets with him at all times and when ever he thinks the bad guys have Kryptonite he releases a few pellets.
If they do not have Kryptonite, no problem. I somehow they do , have Kryptonite, they will be very motivated to get away from it or place it somewhere safe.