It's amazing. There actually is a way to clean tile and grout with out breaking your back scrubbing on your hands and knees.
Warning! The information I'm giving here is meant to be used on man-made tile only. Please do not use the process on Natural Stone.
The first secret is in the process. Most professionals, probably 85% or more, don't clean tile and grout the proper way. That means they don't get the results they should get. Most professionals buy cheap chemicals and expect their high dollar equipment to do all the work for them. The truth is that results are not in the equipment. True genius lies in the details, even when it comes to cleaning floors.
The Process:
If you've ever had your tile professionally, did they do all these steps? Probably not.
1) Apply Step One Cleaner (an Alkyline) liberally to the grout lines. Every cleaner has a "dwell time" this is the minimum amount of time the cleaner is formulated to need to do its job properly. Most will require at least 5 minutes. Apply enough of the cleaner that it won't dry before you get to rinse. If you have a large area, I would suggest doing about 8 to 10 sq ft at a time.
2) Using your long handle grout brush, scrub the Step One solution in to the grout lines. The harder and more aggressive you scrub the better results you will get.
3) Using clean water, rinse step 1 solution off the tile and grout. Then towel dry.
Most of your floor will be now be clean. There may be random places that are not as clean as the rest. Generally these will be high traffic lanes and probably the kitchen. You will proceed to step 4 only for these random dirty places. Step 4 is not meant for all areas of grout, just the one's the alkyline didn't clean.
4) Acid Wash. This is not to be used on Natural Stone. Also be careful not to get the acid on other surfaces. It will damage natural stone and metal and stainless surfaces. So, cover your stainless appliances! If you do happen to get acid on something by accident, it's ok. Just rinse the surface then wipe it down with a rag that has the diluted alkyline cleaner on it. Acid and Alkyline are exact opposites on the acid and base scale, so the alkyline will neutralize the acid immediately.
So, same as step 1, apply the properly diluted acid wash to the dirty areas of the grout. Again, just do one small area at a time. Leave the solution down for about 5 minutes. If you're using a good acid wash you will notice the acid bubbling as soon as it comes in contact with the soil in the grout. Don't let it dry!
5) Using your long handle grout brush, agitate the acid in to the grout lines. Rinse the brush first. You don't want the left over alkyline on the brush to neutralize the acid to soon. You should see results as you scrub.
6) Rinse with fresh, clean water. I actually pour a little of the alkyline concentrate in the fresh water for the acid rinse. This helps with the neutralization of the acid.
7) Neutralize Acid. Using your step 1 Alkyline cleaner, spray the areas you just cleaned with the acid. Quickly agitate it in to the grout lines to get the acid residue deep down, and then just rinse with fresh water.
8) Towel Dry and Inspect. Your grout should be completely clean. Depending on how dirty it was to begin with, it may even be a different color!
9) Now, using a Quality solvent based sealer, protect your grout lines and they'll stay clean for years. not months.
Now you know the process that IICRC teaches in its Certification Classes. What's really sad is that even most of the Firms that are IICRC Certified don't do the job the right way.
The next secret is finding the right chemicals to use that will require the least amount of agitation.
