I'm in need of some assistance from you all please....I have about 15 FIN replacement cartos that I've saved once they'd start to taste bad and need a replacement. I have been looking online and found that you can refill the "pre-filled" cartos by popping off the top with a thumb tack or something similar. Check the cotton inside for any burnt material and so far, so good - still white. Tilt the carto at an angle and rotate it as you add drop by drop to fill it until saturated. Ok, sounds easy enough. Now, how many times can I refill these "pre-filled" cartos before the cotton is shot or the built-in atomizer is shot? What carto brand is a good replacement for a 510 ecig battery and do they come with the cotton and wick already inside them? Any and all help is greatly appreciated!