Mr. Heater Gas Valve Problem

It has cycled several times and has worked every time!

On Wednesday, I checked connections and looked at the pilot. The connections seemed okay and the pilot "looked" as it has for years. (Falls under; "Don't Assume.")

The repair isn't as clear cut as I'd like it to be, but I'll cover what I did. Yesterday, I removed the thermocouple/pilot assembly to blow out the pilot.

-The flare nut holding the thermocouple in the bracket was loose. I don't think that mattered though. I don't think it's grounded through there. The entire heater is mounted to wood, no ground.

-One of the thermocouple wires was loose. I MOST LIKELY forgot to re-tighten it Wednesday when I was checking connections. (Old fartitus.) None of the connections were loose or dirty, so I don't think it mattered that I missed it.

-I think the problem was: Brown dust came out of the pilot orifice when I blew it out. That was probably limiting the gas flow, not allowing the flame to warm the TC enough to ignite.

So you can see it's not entirely clear cut. My complete lack of experience with heaters doesn't allow me to know for sure. Going by 67Dart273's guidance, I'm pretty sure it was the dirt in the pilot.

Thanks to all who responded, ESPECIALLY 67Dart273! I very much appreciate the help. Y'all saved me an expensive service call. (And they may have sold me a new valve!)