"I bought these as favors for my son's birthday party and I was a little nervous reading all of the bad reviews about the bottles not opening. So, as soon as I got them (free 2 day shipping with Shoprunner, yay!) I opened them up to wash them and had no trouble whatsoever opening any of them. Even the kids could do it! The only downfall was that they did leak if tipped upside down, or knocked over. So I wouldn't want them for an indoor party, but for our purposes (an outdoor pool party), they were PERFECT!"