You've replaced your polycarbonate water bottle or baby bottles and sippy cups with aluminum or safer plastic that doesn't contain bisphenol-A, the hormone-altering chemical that's been stirring up controversy lately.But I still have my old bottles lying around and I've been wondering what to do with them. Other consumers are wondering too, out loud on Web sites, blogs and listserves. You don't want to just throw them out and have these chemical-laden things sit in a landfill, and many municipal recycling programs don't take plastics with the recycling number 7 on them, which is the category these bottles fall into. Most charities don't take used bottles, and even if they did it's hard to pass along in good conscience something you are getting rid of because you believe it's harmful. What to do? You could offer them up on your local edition of Freecycle or Craigslist, making it clear that these are the bottles that have Bisphenol-A. With any luck, some creative soul will have found an alternative, non-food use for them. The wide-necked Nalgene bottles are versatile and could be good for collecting coins or holding a portable first-aid kit. Or you could repurpose them yourself. There are rumors circulating on the Web that some BabiesRUs stores are taking back bottles that parents are worried about in return for store credit. A spokesperson said in an email that that the store is adhering to its usual return policy -- no more, no less. Shoppers can return items without a receipt, but the company reserves the right to refuse refunds on these receiptless items at its discretion. This gives store managers wiggle room and might account for the varying degrees of success parents have had returning older bottles.