Hello guys, An important thing that I've learned with cartomizers is that even if you're cleaning them using the syringe to pump water through it it will still keep some of the juice inside of it and overtime it will change the flavor of the juice completely. I was cleaning my cartos to reuse use them at least for 4 full refills. I topped off my cartos with the same flavor and the taste was fine but I noticed that a few of them started to heat too fast or to have a really disgusting flavor. Something was wrong on those cartos, even the new ones (I am only using Boge SR cartos btw). Yesterday I got the proof, and errrrghh... that was terrible. I removed the stuffed thing (that ended up destroying the whole thing anyway), then unrolled the stuffed thing to see how the inside would seems like. I also noticed that the smell was too strong to be the same smell of the juice that I was vaping. For my surprise I found something really "muddy" inside the carto, the smell was terrible and I couldnt believe that I was vapping that thing. Just a few days ago I got a bad soar through so I wonder if it was generated by these contaminated cartos. (well that happened like only 7 days ago and that carto as like new, or only had 2 days usage). I started vaping only about 3 months ago, I tryed to use attys+tanks and it didnt work for me so I moved to cartos and never looked back since. I though that it would be the perfect world and I had found all the answers to my concerns but I was wrong, definitely wrong. As result I got my atty back, filled one tank (510 regular tank+atty) with my favorite juice and vaped away. The flavor, vapor and all the rest were WOW!!!! Needless to say that the vapor production (SR ATTY) was awesome and the flavor was really my favorite juice flavor. I have a LR carto here, and its a double coil but I really didnt like that thing. It heats really fast and made all my juices taste mellow. Bottom line: - I will never use a carto again for more than 4 days straight. - I will never clean and reuse a carto again! (If you saw what I see on that cleaned carto, you would agree) - I will keep using my atty/tank kit (original stuff that I got with my Riva 510 and used only for drip tip/taste new juices) - Its annoying to use atty+tanks but seems to be cleaner and maybe "healthier" due you can see whats happening, when the juice run out and started to taste like burnt. I know that you guys possible have lots of different ways to cleanup your cartos and I've read alot of comments here and watched to lots of videos explaining how to clean it. As result of that you see this topic here, maybe it can be done, but it will not work to everyone or should not be recommended at all! I am only adding this topic here due my health concerns. Once you cant see whats inside the stuffed thing inside a carto, which has the coil, you will never be sure that it will be clean enough or retain some burnt juice that will change the flavor or even create an environment to reproduce bacterias. Suggestion? - Do that yourself, you will destroy a carto but at least you can see how your cartos will be after a few days vaping, cleaning, vaping again... Try that after 1 week, then after 2 weeks to have a good comparison.