Or
Hook up with a local company that does rugs for a living, and has a rug plant. This way not only you can do a bang up job, but look like the hero. There's alot more training for rugs than wall to wall carpet. The low moisture way works, but some rugs will need to be immersed and you can't do that w/ op or in people's home. You can also charge for odor removal, and many other things, new padding, these things will need to be done at the plant.
I make $.50-$4.00 profit like this, but that's what I think works for me.
Here's a tip, if you do in house rug cleaning, inspect the wood floors, chances are there might be some discoloration of the poly/stain, if you do it on people's wood floors, than they move the rug, they will blame you for it.