I've been reading ad nauseam tonight about cleaning grout and your name kept coming up? :)
The best solution I found to clean grout was to dissolve several (6?) "Finish Powerball" dishwasher detergent blocks in bucket of hot water and pour over the tile/grout area and allow to soak for an hour. Had to keep re-wetting off and on.
Too much dishwasher detergent will make floor very slick and harder to rinse off. Not enough detergent and grout will not come clean.
Used a grout brush, long narrow with both sides beveled to center attached to long handle. Grout brush and long handle were purchased from a janitorial supply place (brush $25, handle $10). The wide rectangle grout brushes do not work, they do not get down in the grout line. Was able to stand upright and scrub the grout lines. Takes lots of elbow grease, it does work.
If light colored grout is real dirty, almost dark brown or black it might take more than one scrubbing to get it clean. My grout was off white, think it was called almond color.
Best to allow grout dry completely, no walking on it for a day using fans to help dry, then put a good impregnator sealer on the grout.
Thx SO much. I'm going to roll up my sleeves and have at it.
I'm back. I'm having a hard time finding that brush. Did you buy yours locally or online?
This is the grout line brush I have:
It is UNGER brand. Could not find a number for identification on the brush. I checked the Unger website but did not find the brush. www.ungerglobal.com
The PET bristles are very stiff with almost no give to them.
I bought mine at the local janitoral supply. Also bought the handle at same time. Have no idea whether it will be easy to find a handle or not.
Krissie, you rock. Was able to order from Unger website - on sale!