Beginning on March 25, owners of outdated Dell personal computers will be able to treat them like glass, aluminum, plastic, and paper — by leaving them on the curb for recycling. For $15, Dell will haul away up to 50 pounds worth of discarded computer components (monitors, hard drives, laptops, and the like) for recycling or donation to other users. The plan is an improvement on a recycling program launched by Dell last October, which required customers to drop old computers off at a recycling center and pay $20 to $50. Dell and other computer manufacturers have faced growing criticism over their failure to take responsibility for hazardous electronics waste, which can wind up in landfills or in the hands of unprotected laborers in developing nations. Some critics say the recycling system still isn’t good enough, since few consumers will pay to dispose of old machines.