Do not put caulk on damaged grout lines to repair them. The caulk will eventually get mold and mildew, and the discoloration does not clean out of caulk very well, if at all. You are better off removing the old grout, and putting in new grout.
We cleaned a bamboo silk and cotton rug for a new customer today. They had another cleaner work on it, and it was no better when they got it back. Browned excessively by incorrect procedures. You have to know how to clean these delicate, specialty rugs with exotic fibers. Saved them from throwing away a 3 year old, $5,000 rug.
Well, this made my day! Henry, the son of a new customer, made this beautiful, hand made Christmas card for me. He also made one for my business partner, Mike. What a kind and thoughtful young man - thank you, Henry!
As much as I like cleaning carpet for our customers, there some areas where flooring products like LVT or LVP make a lot more sense for them. These products are great for high soil/spill areas - easy to clean up. Seeing it a fair amount in basements, good if you have messy children...and who doesn't? lol
I do not suggest using any of the oxy type powdered products to spot clean your carpet or rugs. They can remove dyes, especially from natural fiber rugs like wool. When mixed with water, they release oxygen and can make very strong oxidizers to will destroy the dyes. Use plain water, or even better is 70% rubbing alcohol, as is out of the bottle.