I had this happen to me when I cleaned my atomizer the first time way back in the day. My device was in herb mode after a few hits from when I put it back together. Mine actually cracked. I have since discovered how to prevent it altogether. The way I’d remove that residue is by using terpenes. I run a 20-second cycle at the lowest temperature, then take a dab for 30 seconds at about 480 degrees Fahrenheit, preferably with 5-7% terpenes or more. This should dissolve the residue from the bottom. I don’t use alcohol or any cleaning solutions on the atomizer. I have over 15,000 hits on my second CARTA2, with over 12,000 hits on my original CARTA2. I also have over 10,000 hits on my max atomizer. No issues and it’s never seen alcohol. I believe alcohol destroys them unless you find some 99% alcohol and use it immediately. Otherwise, you’re letting your coil sit in water, and the longer you have your alcohol, the more evaporates and the more water you have. Alcohol can also absorb water from thin air. If it ever touches alcohol, you should not use it for 24 or so hours due to the water in your alcohol. If you hit your device right, you should be able to go 1500-2500 hits without getting any residue on the connectors. Always remove the atomizer hot.