Warm Tips: Please check the size before buying. Please clean or disinfect the lid before use. For your health, better to use the lids one time only. For long-term use, it should be dried immediately after touching with water. Write the date or type on the lid of each jar to help you quickly identify and organize. Note: Since our products are packaged and shipped manually by the factory, there may be a slight error in the quantity. If you receive the goods and find that the quantity is missing, please let us know, we will resolve your issue immediately. Reusable or One Time Use? “If you are water bath canning or pressure cooking canning, the lids are NOT REUSABLE”. If you are vacuum-sealing them like on a jar of freeze-dried food, then they can be reused. You are not using any heat to melt the seal and the lid hasn’t been damaged or bent out of shape it can be reused (after a good washing of course) for vacuum sealing again. Canning Process: Put the desired food you need to store, in the mason bottle and put on our lids on the ring cap (not included in our package), please be careful not to tighten it too tightly, so as to better let the air out and ensure the tightness. Heat the mason bottle in a pot under cold water to boil 8 to 10 minutes, then take out the mason bottle and let it cool naturally. Discharge the gas in the bottle when it is heated, then use the principle of thermal expansion and contraction. After the gas is cooled, negative pressure will be generated to achieve the sealing.