HOW DO I DISINFECT MY RETAINERS!!?

Well i just got my braces off and the orthodontist gave me some of those clear plastic retainers and I accidentally left them at a restraunt and they got thrown in the trash and i found them but i need to disinfect them cuz i dont want to get an diseases from anyones food that may have touched my retainers. I need something that will disinfect it without breaking down the plastic. any help?