I've been doing DIY juice for about 3 months. I started out using Flavourart flavoring, 50/50 or 40/60vg. All good. Then I bought some Flavor West green tea and some Faeries black raspberry flavoring. Every batch with these end up gunking my coil and wick before the tank is done. Flavor at 15% down to 5% and still happens. Anyone have any experience with these manufacturers products and is there a secret to using them. I was told use organic cotton at 1 shop, the next said turn up the wattage, goofy. I use a kayfun V4 Tobeco, single coil, 1.6ohm, at 7.5 watts.