Where can I drop off an unwanted Camper Shell?

I am currently stationed on Fort Meade, MD. I am moving and no longer have the truck that had the shell. It is for an Isuzu Hombre (Chevy S10) so is about 6ft by 4ft by 2ft tall. Maybe 100 pounds. I need a dump site that will take bulk items. I have called a few "dumps" but the response is always "I don't know."