Way back they put tin lock washers of sorts over the lug nuts to keep the rear drums from falling off when the wheel was taken off. Most cars/trucks don't have them on anymore. Loosen the adjuster and then the drum should come off fairly easily. A lot of times when vehicles are in storage the brakes get dirty and when driven again occasionally get surface rust on the shoe from the drum. It can be sanded off. As far as grease or differential lube on the shoes, my experience is the opposite. My brakes did not work effectively and when I pulled the hubs there was fluid in them and on the shoes. It was obvious my seals were leaking and after cleaning the entire brake assembly with brake cleaner and scuffing my shoes I checked further and found the breather on my rear axle was stuck closed. Cleaning it and freeing it made the difference. So far no sign of any leaks.
