I used to clean ours so that we could use them with a different flavored liquid the next time around. However, they've never been the same after a good cleaning, the flavors are usually muted and vapor production is usually not up to par with a new coil inserted so now... Very recently we started to put them into plastic baggies, write the date and juice used with that coil and roll it up, rubberband it to keep it rolled up and throw it in the box. The next time that we want to vape we pull out a used coil that was used with the same liquid and use it until it either gets nasty tasting or simply stops working correctly.
I'm honestly finding it's just not worth it to try to clean them, we had a tool box of used coils scattered all over the bottom after cleaning them, we finally tried most of them and tossed a good 3/4 of them as they were totally sub par to a new coil that we tested it against in both flavor and vapor production.
So, if you've got the money to spend, just buy a new coil pack, if you're hard up for cash like I am right now as being unemployed, then put them away when ever you need to switch flavors in your tank(s) and reuse them when you switch back to the same juice they were used with prior until they're either tasting like dirty wet carpets or stop working all together.
Don't get me wrong, I still go through the motion of cleaning a coil once in a while if needed and will use it, for example the night I wanted to switch from Pluto to Hot Cinnamon liquid in my Nautilus tank and I didn't have any (none, zero, zilch) used or new coils laying around), so I gave it a quick bath in vodka for a couple hours and then denture cleanser for an hour and then rinse, dry burn, rinse again and finally drying it in the toaster oven for a short time, and was vaping the new flavor in my tank until I could get to the store the next day to buy a new coil. Nothing wrong with it, but I do notice how flavors are not as pronounced after a cleaning to me, where as one-note flavors like the Hot Cin flavor are easier to tolerate on a cleaned coil since it simply tastes like Hot Cinnamon (or red hotz candies) but just a bunch less strong, where as using it on a liquid that has multiple depth to the flavor often just makes it all muted and not worth wasting the good liquid on it. Just my opinion.
I've had no success with cotton wicks what-so-ever. Tried it on a RDA, tried it with microcoils for things like the Protank 2 and no matter how well I presoak them with eliquid, there is a taste to the cotton when heated that simply is absolutely rank in my mouth and lungs and I cough and sputter for minutes afterwards. Now if I need to rebuild a microcoil and have lost the original wick from it, or I've managed to destroy it by overhandling it I give up on that head and toss it instead of using cotton. I guess my body simply doesn't like the cotton taste where as so many others think it's quite neutral tasting. To me, I can't even express what it actually tastes like... You know... Snake tastes like Chicken, but cotton heated up to me tastes like.... I just can't describe it. It's far worse that dirty wet carpeting when I have a bad coil, so can't really describe what exactly it tastes like but it doesn't work for me.
