I just installed the vinyl tile and used the Flex-Color grout by Mapei. We can't get the floor clean after the grout was applied. The grout was applied correctly and it's not our first grouting job (wife and I). The floor has smears in it, and was wondering if it's the grout that is responsible. The store that sold us this product also sold us the grout as that is what they use. But nowhere on the container does it specifically say that this grout can be used on LVT. We have tried to clean it with water, also with Windex with ammonia as suggested by the store and it just looks dirty. Haven't received an answer from the manufacture but I suspect it will be a sales pitch for their cleaner which I will or course purchase and try. Just wanted an opinion from consumers and not from sales or company rep's.