clean

Hey Y'all, Just got my first enail today! It's a Dabbing Specialist Custom Enail controller. So exciting, but not sure about lots of things. I got a cheap imported quartz banger for it. It's a 20mm coil that's open on the end. I can't get it clean after a dab. Using iso and q-tip like I have...

Good evening. Hope some one can help, please! I already conacter the manufacturer but wanted to see any other suggestions since my unit is out of warranty. How can i clean/remove this please? I tried using my finger nails to scrape it off, but it doesn't, not even a bit. Not sure what it is...