If you use a T18 or T22 tank, you can absolutely clean and re use. They have more cotton in them than any drop in coil on the market. Below is a disassembled coil to show you. If you vape light liquids like simple fruits you can easily run 90-120 mls through them. Then remove the coil. You have to remove the silicone seal on top VERY carefully. There are dual heating elements in the coil, and the upper coil is close to the seal. Just take a paper clip, only go in very shallow and pop the seal out.
Simply put some extremely hot water in a bowl. Throw a handful of coils in. Swirl the bowl around aggressively for a few minutes, then let the bowl sit till the water cools. Repeat process, then leave them soak overnight. In the morning dump the bowl out and rinse with cold water. Blow through them , then put them on a paper towel to dry for a few days. You’ll get another 25-30 mls out of them. Don’t forget to pop the seal back in. Each washing process takes about 3 minutes. Total cleaning and rinsing time is less than 10 minutes . Make sure you let them dry.
Wait 6 months of vaping till you get a half dozen coils to do at once. Ten minutes of labor will then get you another 150ml or more of vaping at zero cost.
Results will vary if you use dark, complex flavors.