How do I keep my babies knees and feet clean after a day of crawling in his clothes? (on the carpet)?

I have two dogs, a dyson, a hoover steam cleaner, dyson zorb. I vacuum everyday, use the zorb weekly and steam clean whenever it gets dirty. But the knees and feets of his clothes are still dirty after a day of crawling. Is there anything I can do to make my carpet cleaner besides getting rid of dogs?