I'm going to go mildly against some of the grain here...
I had an atty die recently. It ran quite hot for a while (but still produced good vapor) and then it finally went soft. A resistance test showed that it had gone up above 5 Ohms.. so I knew that there was no bringing it back. I took it apart in order to make a cartomizer adapter for my 510.
When I pulled it apart I saw that there was a fair amount of gunk that had essentially crystalized at the center of the heating coil. This stuff was as hard as a rock.. almost like glass. It had essentially "killed" the center section of the coil, and only the edges were now getting hot. That led to the edges going incandescent (glowing red), and that led to oxidation of the nichrome and the lost resistance.
That chunk of crystalized gunk could probably/possibly be dissolved in a solvent like alcohol... but it was a hard chunk and it would probably take a long time with a lot of agitation. It was just too far gone in my opinion.
I'm thinking that the gunk built up incrementally, day by day. And if I could remove it day by day... it should be pretty easy. So this week, I have started to rinse my atty every morning with alcohol. No big deal, and so far so good.
I plan on taking this a step further. I'm going to get a small pill bottle and put the alcohol in it. And every night I'm just going to drop the atty in the bottle, give it a shake, and let it soak overnight. Every morning I will blow it dry, put a few drops of liquid on the bridge, give it a few minutes to go down the wick (I know that's a very important step!).. and see how it goes.
I'm not recommending that anybody else try it. Just like Jim Morrison, I will personally go to the edge and bring back the message for you! ;-)