What is Groutmaster? it is the premier tile & grout cleaner that rarely needs prescrubbing. Mix 2-3 scoops, 4-6 oz in a gallon hot water. Spray it down, wait 5-10 mins and run your spinner over it. Cuts greasy filthy grout like nothing else and doesn't harm stainless steel appliances, transitions and cabinets. (Still wipe down any overspray of course) And it's an incredible carpet cleaning booster. Just add 1-2 scoops to your current prespray inline sprayer mix and watch it work magic on rat nasties.GroutMaster will blow your mind as it blows thru thick greasy grout lines leaving them clean and bright. Our special blend of chemicals works great in residential and commercial locations to safely remove dirt and grime from virtually any tile surface. Oh and by the way, its an awesome prespray booster for rat nasty and polyesters. Just add 1 or 2 scoops to your existing prespray mix and watch the magic happen.