Greenwald's Carpet, Upholstery & Fabric Stain Remover Kit contains pre-measured liquid concentrate tablets and is the highest-rated carpet cleaning liquid on Amazon.com. Bubba's Super Steamer Carpet Cleaner is the highest-rated liquid for overall carpet cleaning on the site.
Folex Carpet Spot Remover by Allstar is the highest-rated liquid spot remover by customers of Amazon.com.
HappyMoneySaver.com lists a homemade solution for machines that includes 2 tablespoons of Tide laundry detergent, 1/4 cup of Awesome Cleaner, 1 scoop of OxyClean and 1 teaspoon of Downy fabric softener. Users are directed to mix the solution in one gallon of hot water before adding it to the carpet cleaner tank according to the site.