I don't know, but mine come up looking like new, and taste like new too. My process: Wash in boiling water Air dry overnight Dry burn Wash in boiling water Air dry overnight For a dripper you usually have to forego the air drying stages and just blot them as dry as possible. Under no circumstances skip the two washes though. There's no point trying to dry burn a wick that is covered in juice, and there's not point trying to vape on burnt ash. The first wash gets rid of juice in the wick, the second wash gets rid of the ash. ETA: When you dry burn, do it till smoke and smell stops coming off the coil, then keep doing it until the ash stops changing colour - it usually means all the crud has been converted to ash and is ready to be washed away. Pulse the coils for about 1 second each time, or longer if they can handle it. They need to glow quite strongly, and across their entire length.