I've had good luck with the following method to clear a flooded carto. In severe cases I've gone through the process several times but it's always worked.
Take a single square of toilet tissue. Grab one corner and twist between your thumb and forefinger, in one direction only, to make a very fine rolled tip. Insert into the battery end of the carto and twist gently in the direction you wound the tissue in and carefully push it up as far as you can. With my Ikenvape std cartos I can get it in at least an inch. Leave it there for 30 sec at least and remove. Repeat until clear.
If possible, increase your wattage. For me this would be 4.9v on a 2.2ohm carto. Take long, slow hits. Deal with a couple hits that taste burnt. Set it down and repeat in 5 min. You should then be able to return to normal wattage, for me that's 3.7v on a 2.2 ohm carto.
I use 100% VG with 2 hole Ikenvape cartos, works beautifully.
I've brought cartos back from the grave with this.