Has your toddler outgrown their current car seat? Is the seat you're currently using covered in juice stains and cracker crumbs? Are you finished using car seats with your kids and looking to purchase something else they need?   Walmart is gearing up to help with their car seat trade-in event, running from September 16 through 30 at more than 4,000 participating Walmart stores.   Parents who trade in a used car seat at their local Walmart will receive a $30 Walmart gift card to use on the purchase of a new car seat or other baby items. The traded seats will be recycled by TerraCycle, a waste management company that works with major retailers to find ways to recycle items that are challenging to dispose of and may otherwise be thrown into landfills.   This is the first car seat trade-in event held by Walmart, and is scheduled in conjunction with National Baby Safety Month.   "Safety — especially car seat safety — is a top priority for Walmart's baby department, so we wanted to use our size and scale to create an event that offered unprecedented access to trade in an outgrown car seat for a gift card — perfect for using on your baby’s next car seat," said Melody Richards, vice president of Walmart Baby. "Sustainability is of equal importance to Walmart, so we're happy to work with TerraCycle who will recycle every component of the car seats."   To take advantage of the deal, Walmart customers can bring their old car seats to the customer service desk of any participating Walmart and receive their gift card. Booster seats are not eligible for the trade-in, and there is a limit of two gift cards per household.