Cleaning grout stains off porcelain tile

[Govinator3]

All right, I'm hopping I haven't ruined my nice tile.

I've just applied polyblend unsanded charcoal grout to my 3/4 x 1 9/16 unglazed porcelain mosaic tiles. Now the white tiles are gray.

I applied one coat of miracle 511 impregnator using a rag to blot it on.

I'm assuming I need to let the grout dry then apply a 50/50 vinegar and water mix then scrub with a brush. If I scrub now I just kick up more wet grout from the joints.

If the vinegar doesn't work what would my next steps be?

Thanks,
Mike

[cx]

You applied the sealer before or after the grout?

[Govinator3]

I applied the sealer 2 days before I grouted.

[Govinator3]

So last night I did 2 coats of 100% vinegar. I allowed the vinegar to sit for 10 minutes, I added Aqua Mix Nanoscrub and agitated for 5-10 minutes with a stiff nylon brush. My picture is kind of dark but there is a new loose tile sitting in the middle of the pic to compare the color. Overall the floor is much improved, we still have some discolored tiles but it is alot more muted. Eventually I think I will go to sulfamic crystals. I found this website in the UK describing a cleaning method that I plan to use. http://www.tileandstoneblog.co.uk/po...rcelain-tiles/

Basically you use a solvent stripper to soften the polymer component in the grout, then apply your acid to attack the cement, then add your nanscrub for mechanical cleaning. It made a lot of sense to me.

[cx]

The industry recommendation is that you not use any acid on your grout until it (the grout) has cured a minimum of ten days.

Your new cleaning method (I did not read the link) may help you clean your floor, but it will most certainly also weaken your cementitious grout surface substantially. Up to you whether you try it.

My opinion; worth price charged.

[Govinator3]

Cx, thanks for you responses. I used the vinegar after 4 days of curing. My thought being that the vinegar would be mild enough to be acceptable. If I do decide to pursue using the sulfamic acid it will definitely be after 10 days of cure time. 90% of the tile is not visible since it is under a clawfoot tub so I might just give up on getting it any more clean.

[davidmack]

You can use sulfamic or phosphoric acids. Try a small area at first to see if that will even get it. These are still relatively safe for use by diyers.

If you need to go to muratic get a REAL professional to do it. That is nasty stuff and can do damage both to your health and home if not done correctly.

[stu rosen]

You Haven,t ruined your tile-You will need a good acidic cleaner to take the residues off.
You will need to repeat the application most likely.
Some elbow grease and a black pad may help.
Stripper wont hurt it-not sure if you need it.
Be carful with nano scrub as it can got stuck in your black grout.