Ugh, I feel completely stupid. I made a big mistake while brazing in the suction line on a new evaporator coil. I had used a Kleenex to stop debris from getting into the line while cleaning the end, and I forgot about it and left it in while brazing. . I was flowing nitrogen through from the suction line, through the evaporator coil, and by the time the smoke had made its way through the coil, I was mostly done with the braze.
I did a test with the same pipe configuration and nitrogen flow on a scrap of pipe, and I found the charred kleenex gets blown somewhat back. I'm not too worried about that, that can be blown out. However, the tar from the charring condenses on the inside of the pipe, and even after blowing it out, still smells very strongly.
Is there any way to salvage the evaporator that now has tar condensed in it? My test pipe cleaned up relatively well with acetone. Is there any way to clean it, or do I need to replace the evaporator?