I see 70-year old female FAs do it every year at training.

Exit must be removed, pulled into the cabin, swung through the window opening (to simulate throwing away from the aircraft), brought back in to cabin and placed on the armrests in one continuous movement while being observed one-on-one by the trainer/tester.

Window exit has handles and is a solid object, much easier to handle than an amorphous bag of shifting birdseed.