sorry, are you guys talking about the bottles that have a cork and screw cap or just screw cap? my family got a case of welch's sparkling grape juice with screw on caps. i rinse them in hot water and use. my first in these bottles was not done, so i would release the gas every so often. every day or so. we know that releasing carbonation can build quit a bit of pressure. but i've heard of wine bottles exploding. so i guess carbonation isn't as powerful. and with a cork, the cork may blow out. besides, i hate corks.