If you like your carpet - never use "Steam Cleaning Vans" services. Their 212 degree steam will burn your carpet, set stains, can cause wrinkling and ... spreading dirt with a pad and not rinsing... no way!
Your carpet needs to be rinsed properly with a
clean water or vinegar solution to remove sticky soap film which attracts dirt like a magnet.
AND: only good scrubbing will remove spots and stains completely.
So, instead of using Steam Cleaning Vans, try to use carpet cleaners for household. One of the best (maybe the best) is
Hoover SteamVac V2. Or use
Dry Carpet Cleaning.