Thrift Shops and Flea Markets Carry Numerous Chargers . . .

. . . and might have a match for at least some of your phones. You can also try contacting the manufacturer, or post on Craig's List. Local sheriffs, etc. often accept phones for, e.g., abused women, where only 911 is accessible. But they'll still need a way to charge them. Good luck, and thank you for disposing responsibly.