We have carpet in one particular bedroom, that right when you walk into was BLACK. From pets using the bathroom there from the previous owners not taking care of it. I thought I was going to have to buy all new carpet. After one use.. I could NOT believe the difference. I vacuumed a small 2 by 2 area once, and it was already so much lighter. I emptied, cleaned and was back at it within ten minutes and even MORE came up. I eventually did the entire room, and it looks like a brand new carpet. It was easy to do, easy to use. The cleaning process was quick.