The answer to 'upholstery greasy' is that upholstery can become greasy for a few common reasons, such as skin oils, cooking grease, and pet hair and dander. This grease can build up over time and make the fabric look and feel dirty. Symptoms include a shiny, discolored appearance and a sticky or tacky feel to the fabric.
For minor greasiness, you can try DIY cleaning methods like using a mild detergent or upholstery cleaner and a soft-bristled brush. However, if the grease is extensive or set in, it's best to call in a professional cleaning service. They have the specialized equipment and techniques to deep clean the upholstery and remove stubborn grease without damaging the fabric.