Due to their pressurized contents, charged fire extinguishers cannot be disposed of your regular trash. Fire extinguishers that were manufactured before 1970 may contain the toxic chemical carbon tetrachloride and should not be discharged.
York County business, BFPE International at 3466 Board Rd, 17406 accepts fire extinguishers of all ages, conditions and types for recycling. Contact them at 717-741-9980 or click here for more information. You can also contact your local fire department to dispose of an expired or unwanted charged fire extinguisher.
If you are sure that your fire extinguisher is completely discharged, contact your local scrap metal recycling facility to ask if they will accept it, or place it in your regular trash.