As Mara and I said, we use the oven. You aren't really 'baking' them, only drying. In humid areas, this method is at least, consistent for us. Gert thin down your icing and put a real thin coat of icing on the cake to seal in the crumbs. Spatula as smooth as you can make it.
Pastry bags are among the most useful and versatile tools of the kitchen.
Besides decorating cakes, you can also use them to fill appetizers like stuffed mushrooms, fill eclairs or cream puffs, and craft uniformed drop cookies like macaroons. Fat-based fillings work better with polyester bags because they're thicker and they protect the grease from seeping through the bag as the heat from your hands warms the filling. Tubes ensure proper and consistent size when you're making drop cookies or decorating cakes. When uniformity is not as important, such as when you're filling mushrooms or jelly doughnuts, you'll want to go tubeless. Without a tube, you can also add fruits, nuts or even chocolate chips to your filling and they'll easily pass through the opening.