The suction of a vacuum cleaner is what picks up dust from your carpeting. Some carpet cleaners have a spray to focus on the dirtiest of areas.. If your carpet is really dirty and looks like it has greasy residue on it, a vacuum cleaner may not be enough to make your carpet look respectable again, so you should consider a carpet shampooer. After the shampoo has dried the rug can be vacuumed. If you use a carpet cleaner your rugs will be far cleaner than if you just vacuumed them.