If you follow the instructions with the refiller and add a few precautions such as storing them in a well ventilated area, testing each one with soapy water, and even using a small scale to ensure they are not overfilled, then you wil be ok. At less than a buck to re-fill compared to 5 bucks for a new bottle, you are not only saving money, you save them from the garbage. A five lb tank is a better solution but when I'm pulling my ice sled the less weight the better........