I would expect professional cleaners to use their chemical feed to introduce rinse agents into their solution line but those Neanderthals who don’t prevacuum use
Prochem’s Dry Slurry.
Let me translate this with kindness and tact:
Today, most cleaners introduce a product that serves as a rinsing and neutralizing agent. Some formulas may also have additives that restrict wicking, and a few have cleaning properties as well.
Should you find yourself cleaning carpet that is grossly soiled, and where you feel that dry vacuuming, then thorough preconditioning with a suitable detergent/solvent blend made for that purpose is inadequate to the task, I have found Prochem Dry Slurry to be a very good product.
44 years after its introduction, it remains the top selling product of its type at my supply house, though these kind of cleaning agents have declined in their use since the advent of the aforementioned rinse/neutralizing/anti-wicking solutions.