it has already been 3 days since the grout was applied. I'm thinking that is probably too late for the "low tech" solutions? Does any one know which of the commercial products might work? Pros and cons?

Believe it or not, the "low tech solutions" will still work. The higher tech solutions aren't DIY products. The one I use isn't even available to the general public.

Thanks, Bill-- when I searched online, I found recommendations for the vinegar solution that said it had to be done within 48 hours. Also found some commercial products (4 of them), but didn't notice that I couldn't buy them since I didn't try! Our tilesetter said toluene would work, but yeah, it is pretty toxic. I am certified to work on hazardous waste sites and have a full-face respirator, but still-- I'd rather use vinegar if it will do the job!

The one I use is a product called Petra 7, made by a company called Dominion Restoration. It's not really toxic at all. In fact, it has a very pleasant citrus smell to it. The problem is that first, it's a highly concentrated product, and if not mixed properly, could turn ANY tile floor, no matter how abrasive, into a skating rink. Secondly, if it's not completely rinsed off immediately after the cleaning is completed, You could literally come in the next day and find every epoxy grout joint soft enough to scrape out with a butter knife. It's that strong.

Send Laticrete an e-mail and ask them. I've found their customer service to be quick and knowledgable.

Laticrete will tell you to go with the vinegar solution.

Today my tile supplier told me to use Aqua Mix Nano Scrub. Haven't yet tried it but intend to.

This may be an old post, but I have solved my problem, it may solve yours as well.

I used CEG lite grout, from Home Depot where no one knows what the hell they are doing since HD fired the older employees that did know and replaced them with $9 an hour employees.

I had installed the grout as directed. no matter what they said I still had grout haze in some spots. After research I found nothing that helped, the vinegar and water didn't work, nor did elbow grease.

My tile is matt finish and the expoxy haze was shiny with a few 'lumps' that needed to come off. The grout had been on the tile less than 48 hours, so keep that in mind.

I used lacquer thinner to remove it with a clean white terry cloth. I put a little lacquer thinner on part of the cloth and started wiping it up. It wasn't hard, but I was judicious in trying not to get it directly on the grout lines.