I've had my Pax for over a month and I have had no issues with it so far, no sticking mouth piece, no temp. button problems at all, if you clean it the way your suppose to I don't think there should be an issue, when I use the pipe cleaner fuzzy stick (whatever you want to call it) I dip in ISO and with a tissue wipe off the excess ISO so the pipe cleaner is damp but not saturated, so when you put it in the vapor tube drops of ISO don't drip off the stick and I also never push it all the way through, I allow the tip I inserted in first to reach the end of the vapor tube near the temp. button, just so it peaks through and pull it back down, this allows for no ISO to get left in the vapor tube ditch next to the temp. button, you can clean the mouth piece by dropping it in ISO for a few minutes, this will do no harm, clean the oven with a q-tip and ISO, hell I even used a q-tip with soap but just damp with no excess water and soap on the q-tip, squeeze the tip with your fingers then dab in the oven, pretty simple, I clean after every use so I never see any residue, if you use wax or oil or concentrate then good luck, I honestly don't think the Pax was designed for it, only flowers.