Bob, Angus,Rob,Chair..... Thank you for the ideas.
(Chair... Thanks for the info... little above my need/capacity for one residential redo.)
So, I just got back from playing with Oxyclean and Clorox.
...(Bob, actually I was using Krud-cutter before... don't know why I got mixed up and called it Ka-boom... it took up alot of dirt,,, but not that great on the grout)).
Oxy did better, but Corox really cleaned up the grout stains REALLY.!!!
I guess my first question to you guys would be... how bad do you think that bleach compromizes the grout. The grout has been down for many years and is fully competant right now.... Would I expect it to crack/crumble at this stage.
Depending on your guys advise, I may go ahead with Custom's colorant,... more so for grout integrity, rather than color aesthetics.
I'm reluctant to follow up with the colorant if I don't need to, for both the time/work, but more so, because the tile is a very rough/ textured (non-skid) porceline .... and I'm afraid of being able to clean the tile with an epoxy based colorant.
Thanks again
Peter