Shampoo'd the rug

Today I set aside the day to shampoo the 8x10 rug we have in the living room. We've had this rug since April 2007, so it's only about a year and a half old, but we have two dogs and the rug is in front of the front door so it gets a lot of traffic. I rented one of those machines from the grocery store and I have to say the results were just gross! You can see the water that has been extracted from the rug and it was more like black sludge in our case. I couldn't believe how bad it was after only a year and a half! Since I had the machine, I did the sofa too which was also quite dirty. It's at least 10 years old and has never been cleaned. It also had a ton of dust which is ever present in our house due to construction.