I refill my Cig2O cartridges.
My 'tools' were a couple of items I had laying on my computer desk. I use a brass, screw in hook to pop out the back plastic cover. I also use it to remove the silicon donut seal from above the stuffing.
Always save the end caps for your cartridges.
The end cap the does not have the center dongle in it is what I use for refilling. I fill that cap about 2/3 full with liquid. I then push the cartridge in open side up. This way, I can watch the e-liquid to see how well it is soaking into the stuffing. If it soaks all of it up, I use a medicine dropper to add drops until it's full. Once it's full and not soaking up anymore, I lift it up slightly in the cap and then gently blow into the cratidge. This pushes any excess liquid back into the cap so I don't waste any.
Once that's done, I put the donut back in and use a 1/4" allen wrench to seat it level at the top of the stuffing and then reinstall the end cap.
I then place a kleenex over the contact end 9aka the end that screws tot he battery) and give it a good blow into the kleenex. This gets rid of any residual the gentle blow didn't get out. It prevents over-saturation of the element and also prevent you from getting a good dose of e-liquid in your mouth the first time you go to puff on the new cartridge.
I then take the kleenex and double over an edge. I have a paper clip that I unfolded and I use that to push the kleneex into the groove between the outter sleeve and the center conductor. I run it around the entire groove to clean out any residual liquid hiding in there. That can clog up the three vent holes on the battery if not cleaned out.
Wipe off the outside of the cartidge, cap both ends, and you're ready to go
To clean the groove of the battery, use a stadard wooden toothpick. Advisable to poke it into the three vent holes first and then clean out the groove.
I generally get 10-15 refills from a cartridge before I feel the need to clean it. I use a 10cc syringe (no needle) and Everclear.
Do not use denatured or isopropyl alcohol. Those are unsafe for consumption and dangerous if inhaled.
Everclear is 95% proof. The other 5% is water. Pop the end cap off and take out the donut. Use a full 10cc's and squeeze it through the cartridge from the open end. I usually do this 2-3 times per cartridge using a small bowl to catch the Everclear as it goes through. I leave the caps and donuts off for few hours to let the cartridges dry.
I've got some cartridges I have been refilling since April and still working great
