Well, it finally happened: you know how I like to poke used, dying cartos with a pin to get them to work again? Well last night, I poked a little too hard, and POOF, out pops the coil on a couple of them! Oops! Oh well. Time to experiment.
Whoa, charcoal briquettes! I thought they were burnt, but I think they're just encrusted with almost two months worth of crud. Yeah, I could just throw them out after that long, but figured it would be nice to find a cleaning method that's actually effective in general, if I'm gonna continue to clean them at all.
So, since this blackened coil is what really needs to get clean (the batting is easy and won't necessarily bring a carto back to good working condition), I tried soaking it in:
- Vodka for 4 hours: No effect. Still hard as a rock. This is what I've been using. Obviously, it ain't working!
- Rubbing alcohol for 4 hours: Same thing.
- Dawn and hot water for 2 hours: wow, the fiber thing that the wire is wrapped around completely cleared up at the ends, but it's still black and hardened where the wire is wrapped around it (bb got a little smaller though). Maybe soak a little longer. But it would be such a pain to rinse soap out of a carto, what with all that batting and all! Hmmm...
- Sprayed one with Easy Off: crud's completely gone, but yeah, like I'm really gonna clean my cartos with Easy Off! Too young to die.
- Soaking in a denture cleanser tab now (thanks, Rave). One hour so far, and no effect (still hard and crusty). We'll just let that sit overnight and see how it goes, cuz I had high hopes for this one...(works great on my french press though)
- E-liquid that I didn't like...they put PG in soap, right? Must not be not one of the active ingredients, cuz it ain't doing a damn thing! ...yet. We'll let that sit next to the denture tabs.
So what I'm thinking is to approach it like I'm trying to clean a baking pan with really nasty burnt/hardened/baked-on sugar, cuz that's pretty much what it is, right? And it's not like you can get in there and scrub it off, so it would have to get clean by soaking. So the trick now would be to find the right solvent that won't kill me...hmmm.....hydrogen peroxide? vinegar?
I use the vodka/sonic cleaner version but I DON'T wait two months to clean them! 
as you so eloquently named them, great description. 
Vodka soak overnight, flush with syringe (like Vapian's fillinator) and very hot water, flush with air using syringe then air dry for two days. I'm pretty impressed with the longevity of the Volt cartos. I've only used about 15 cartos in that time so they've seen some solid use, lots of refills, and even some flavor switches. Performance is close to new after cleaning but taste isn't quite there. It's acceptable but probably time to get a some new ones coming. I guess if I'm only buying one 5-pack of cartos every month or two that's not bad at all. 
