If you fill a Joye 510 cartomizer this way, you are not filling the reservoir, you are filling the air path. It "works" but you get gurgling and you've only put in a drop or two into the filling, so it won't work for long. I think you guys are confusing "Joye 510 Cartomizer" with "510 Cartomizer". The new Joye 510 Cartomizer has a "filling port" which needs to be pierced, and then filled with a syringe or small pipette...