If you are looking for the best carpet shampoo, we would recommend the BISSELL 2X Concentrated Professional formula with scotchgard. This is Bissell's best ever deep cleaning formula, now containing double the quantity of non-volatile cleaning agents for professional style results. Dual action formula deep cleans and protects in one easy step. The BISSELL Professional carpet shampoo is universal, having been laboratory tested and found safe to use in Bissell, Vax and all other brand full size carpet cleaners, even rental machines. IF you want to get the best possible results from your carpet cleaning machine, you owe it to yourself to try our best carpet shampoo ever.