I am surprised to see this post - even when I had a room full of snakes I never had any odors whatsoever. I primarily use paper substrate and the whole cage gets changed out each and every poop or urine.
I would switch to the Uline indented kraft paper to ensure you are catching every pooper as it happens. Something must be lingering in the cage for it to smell like that and that can't be healthy for your snake either.