Smartseal Grout Magic – Black, 237ml – Professional Reviver & Colour Restorer – Long-Lasting Sealer Superior to Grout Pens & Paint – 15-Year Durability

This grout dye has worked perfectly - my bathroom floor looks like new. I have black tiles which had mismatched grey and white grout - it looked very shabby. I was concerned the colour may be uneven as I had two different shades of grout originally - however this was not a problem. I applied two coats (leaving an hour in between) with a small artists brush. The residue on the tiles I wiped with a disinfectant wet wipe. after 48 hours I have washed with water and bathroom bleach.As I had black tiles and was a applying black grout, it was not so much of an issue if the dye left marks on my tiles. I think this product would be more difficult to use if you were applying the black dye on white tiles! It is very difficult not to overspill onto the tile and I am not sure how easy it would be to wipe off. Be very careful to use a precise brush in the case

The product absolutely works and you can get a good finish, but how it comes out is completely down to your preparation, method, and how good the grout has been done in the first place.Firstly, you need to clean the grout thoroughly, if there's any grease on the kitchen grout or slime on the bathroom grout then it will not penetrate and will come off when you rub off the excess. As someone else in the reviews has said, a wire brush (I used a firm toothbrush) is a good idea, a scourer at least.Secondly, the instructions say that you can remove the excess immediately but I haven't found that to be the case. It needs a good 45 minutes to an hour to soak into the grout, and at least two coats.Lastly, and this likely only relates to darker colours; if your grout is poorly done (as mine was) then making the colour darker show up the poor workmanship. Excess grout on the tiles will show way more and uneven tiles will become more apparent. If you're doing white on white then you should be fine.A decent product, but needs to come with MUCH better instructions and support - a guide video would do the trick.

I used black to revive the grout around white tiles. It looks fab where the tiles are whole ones. I took a razorblade to the grout to tidy it up first. Unfortunately after starting I realised that the tiles were VERT badly cut and all the chips and jagged edges are now painfully obvious. Just be aware before you go for dark grout that if your tiles are not cleanly cut, it dark grout will show this up. The product does a good job though. I couldn't find any other way than using a shed load of paper towels to wipe up each tile afterwards though. Maybe a huge stash of rags would be a better option.

Instructions very vague and product quite inconsistent. A lot pulled away from grout when wiping excess or smeared unexpectedly. Resulted in a lot of scraping etching and applying three or four more times

Tried this and done exactly what bottle said, once cleaned it wiped off in places.

Easy to use once you get the hang of it..just don’t leave it for too long without wiping as it’s a bugger to get off once it’s a little more set. Much easier to do little sections, doesn’t have to be neat and don’t put it on thick just use a small brush to dab it on and make sure it’s spread out and pushed in to the grout, leaving it a couple of minutes to start setting and then wipe each section as you go. Looks lovely once it’s set, really pleased!

Looks okay stood back from tiles, but up close not fantastic. I am now removing tiles as decided they gave had their day. Worth a try tho.

This was so easy to use and has made such an impact on my yellowing grout that was there. It is well worth giving the grout a really good scrub first. I had a few patches were there was a grease build up from the previous people and I had to redo the area as it didn't get into the grout properly, other than that it was a breeze to do. I will be buying the grey soon to do my bathroom!