Chevrolet Repair: 92 Cavalier rear breaks, rust buster, brake drum

Question
I am trying to troubleshoot a leak in my drivers rear breaks and am assuming it to be coming from the cylinder.  (There's nothing coming from the nipple) The problem is the drum isn't coming off and I dont want to damage it.  Is there a clip or something retaining it somehow? While I start to pry it moves but seems to be held in the middle. The wheel spins freely so I know the shoes aren't making contact.  

Answer
rust tends to buildup around the center hole of the drum where it fits over the axle.

Purchase some RUST BUSTER or similar spray can product and liberally spray around the cenetr hole of the brake drum at the axle and tap on the brake drum LIGHTLY with a hammer and it will slowly break the rust away and the drum will come off.