[qwerty]

What does the friction surface of the drum look like? Should be clean metal. Any rust/crud/oil will ruin the brakes.

 

[qwerty]

How clean was your dry rag? Was it treated with a chemical to pick up dust or increase absorbancy? Had the surface of the rag you used to wipe the drum previously touched your hand? Natural skin oils can be enough to reduce braking effectiveness--drum surfaces should be cleaned with brake cleaner. Shoes should be cleaned with filtered, dry air. Never touch friction surfaces on either.