Thanks for the info.
I've never seen any cat of mine that looked like what I see in his 006.jpg and 010.jpg. Too bad he didn't try to simmer it out in the vinegar/water solution to see if that made a difference. (Would have given us a better look at what is under the fly ash, too.) What
has been confirmed by Highbeam is that in the third year, his cat wasn't burning as cleanly as it did before. There has to be a reason for that, and for what appears to be a crack in the face of the cat (not sure that's the case.) The diesel-foil cat (which you dissed) in my BIL's Fireview has got 4 years on it. He's shriveled it, but it still burns clean. Highbeam says his wood is dry. Maybe he had a leaking door gasket, but I'd have thought he would be keeping an eye on that, since it has been mentioned in several threads. That might cause cracking, but not failure. What we don't know is how he runs his stove. This is his first cat stove, and he's now found that he's done something that fried his cat in three years, and maybe it's not a simple as just running the cat probe up to the active line and closing the bypass. I also wonder about the advice to run the stove wide open for an hour, with the cat engaged, once a week. That just sounds to me like it would pound the cat with massive amounts of heat. But like I said, I'm no cat expert, just pondering...
If we move on, what have we learned, besides the fact that he put in a new cat and it worked? I was hoping to find out why the other one crapped out so quickly, so maybe I could operate
my cats better. I assume you see reports on returned, failed cats. You have seen thousands of these dead cats, and probably have a pretty good idea what happened in this case, but I guess I can't really expect you to acknowledge that there is a way to screw up when running one of your stoves. Your stock-in-trade is the idea of a simple to run, thermostat-controlled, set-and-forget appliance. Your job here is to present your product in the best possible light, and to try to find a solution when people are having problems with your stoves, to reassure potential buyers. Me, I don't care if it's harder to run a cat stove; The payoffs are huge and I'm a cat guy all the way. I'm just not yet willing to buy into the BK hype like some of the cat newbies around here have....
His Cape Cod was a different kettle of fish. And that's really where my "hype" comment was aimed; Guys that try a cat stove after they have had tube stoves are totally blown away by the performance and they become instant fanboys of their new 'miracle stove,' be it a BK, WS or whatever.
My tendency to call 'em like I see 'em and my lack of people skills are a couple of the many reasons I was never a VP of anything. 
