While the previous suggestions seem like the obvious solution, they don't really satisfy your "responsible" criterium. Brake fluid and anti-freeze seriously interfere with the processes used in the recovery of lubricating oils for recyling. I'm sure many recyclers will reject loads contaminated with glycols. It's also problematic in waste oil burners. Find a responsible shop that will let you bring it to them. Safety Kleen and the like handle it in a separate stream. You might contact them locally for a suggestion on a shop they deal with. You might have to pay something, though. I haven't had to find a home for mine yet as I'm not very good about regular flushes and only generate waste fluid from incidental tasks like bleeding after component replacement.