i refill carts all the time. some work and some do not. i purchase ink that is manufactured to the specs of the original. sometimes the consumer does not take the necessary precautions to protect the printhead for refilling, which is why some do not work. once the consumer is educated on how to protect the cartridge and the printhead, then theirs have a better success rate. at the manufacturing plant, the ink is inserted into the cartridge and then the lid is glued on. some of these cartridges have been bougt back and are being refilled, some are new. with lexmark cartridges, you pop the top to refill the color and on the black, you just need to enlarge the vent hole to insert a syringe of ink. same on the newer versions of HP. however, on the older versions of HP you have to maintain pressure, by removing any excess air. there are certain tools you can buy to do this. as far as bugs . . . i have no idea what you mean. sorry. hope that helps.