I last used clear shot many years ago. I had a problem in my TC Hawken .50. I'm not sure how many shots I fired, but I at last had a FTF, and after snapping several caps I finally gave up and pulled the ball and dumped the charge. What I discovered was that a clay-like fouling had built up in the breach to the point where the flash hole was obstructed. I wasn't terribly impressed. I was going to use the remainder in my BPCR gun, but a quick search suggests that it isn't terribly friendly towards brass, with suggestions of ammonia in the residue.
I keep looking towards substitutes and yet I keep ending up back at black.