Walter: This is gonna be a long post cuz removing grout sealer is something I've done a fair bit of.

You asked: "What do the pros use?"

No one makes a living doing what you're trying to do. So there are no "pros" at this. The closest thing would be a janitor...

...or a landlord.

Seriously, I wouldn't start removing any grout with a power tool just to remove the sealer on it.

If your sealer is peeling off the grout, then what you have on your counter tops is a "film forming" grout sealer (as opposed to a "penetrating" grout sealer). ((Penetrating grout sealers weren't very common 30 years ago.))

Now, film forming grout sealers come in two flavours; acrylic and silicone based. That is, the plastic they're made of will either be the same plastic that Plexiglas is made of, or the same plastic that silicone caulk is made of (which is technically called "siloxane" nowadays).

So, since top quality latex paints are also "acrylic", if your grout sealer is acrylic, then anything that removes latex paint will also remove your grout sealer. Take some nail polish remover, or buy some acetone at any paint & hardware store or home center, and apply it to your grout line(s) and scrub with a green Scotchbrite pad



which you can buy in any super market for scrubbing pots and pans. I'm suggesting you use a Scotchbrite pad instead of a tooth brush or denture cleaning brush because Scotchbrite pads won't spray tiny droplets of acetone all over the place like a stiff bristle brush will.

Be careful using acetone. It's highly flammable and it'll dissolve a lot of different stuff, so don't spill any on your floor. Maybe pour some acetone into a large mouth container outside or over your kitchen sink, and then dip a piece of Scotchbrite pad in it and scrub your grout lines with that. Use a resealable container cuz acetone evaporates fairly quickly so you can't leave that container open overnight or even open for a few hours.

If the sealer is removed, then you can continue using acetone, or lacquer thinner (which evaporates more slowly) or xylene (which evaporates even slower) instead, or switch to a methylene chloride based paint stripper like Polystrippa. All of the previously mentioned solvents evaporate completely without leaving a residue. The active ingredient in conventional paint strippers is methylene chloride which also evaporates completely without leaving any residue. If you find any residue left by a paint stripper, it'll just be the gelling agent, which you can remove with mineral spirits (which also evaporates without leaving any residue).

If the sealer doesn't come off, then I'd assume it's a silicone based grout sealer, and use this stuff on it:



or...

http://external.ak.fbcdn.net/safe_im...fL._SL500_.jpg

both DAP's Silicone-Be-Gone and McKanica's Silicone Caulk Remover Gel are basically gelled mineral spirits, and you should be able to find both of them in the caulking aisle of your local hardware store or home center.

Now, I've never used a silicone based film forming grout sealer (and I don't intend to start), so I have no experience removing silicone based grout sealers. We'll have to play this by ear in that respect.

However, I have acrylic film forming grout sealers in all 21 of my apartment bathrooms, and I've had plenty of experience removing acrylic grout sealers from the ceramic tiling on the walls around the bathtubs in those apartments. You might not believe it, but if you have the world's worst chain smoker as a tenant, the acrylic grout sealer on your bathroom ceramic tiling can get smoke stained just like the acrylic paint on the walls of that apartment.

So, do the acetone test and/or the Silicone-Be-Gone tests and post again.

Once we know what kind of grout sealer you have, we can talk about the easiest way to remove it. And, we can talk about the two best acrylic grout sealers (in my view) to put on.