Based on the shiny appearance I would guess it has some sort of sealant or polish. What's throwing it off are the white areas at the left of the picture and near the person's feet. I'd start with the steam mop in a small area that will be covered by furniture to see how it reacts. I'd do the same thing with other cleaners: small areas first. This link has some good directions: https://www.doityourself.com/stry/how-to-clean-brick-flooring

That's been sealed. If you're going to use a cleaner, the best one to use is oxyclean. Mix a pail at twice the strength recommended on the side of the package. Then hit the floor with a scrub brush and really agitate it. Once you've done that, use a wet vac and suck up what you have on the floor, so that you don't just push the dirt back into the floor. Then do the same thing all over again using clear water. That floor should be as close to like new as you're going to get.

Having a pro strip and reseal the floors is worth every nickel.

I want to follow this. SJ, can you recommend a professional-grade product for the brick floors that would give less effort to maintain?

Thanks.

Sorry but I'm a "wood girl" not a brick or stone gal. You can reach out to a stone and tile company that deals with residential and commercial maintenance. Brick is VERY porous. I mean LIKE A SPONGE type of porous.

When working with brick you do NOT want to do "least maintenance". Because there is no such thing with brick. It's like trying to find marble that doesn't etch or stain. It just doesn't exist.

Maintaining brick is just part of it's charm. My suggestion is to have a lengthy talk with someone who does this for a living and find out what THEY would do if they owned a brick floor. And then go out and PURCHASE all the products and all the machines that would be needed to maintain the brick to the HIGHEST level. Learn how and when to use the products (?pay for a tutorial?) and then you can rest easy knowing that you have everything on hand to do what needs to be done - whenever you so chose.

Remember Grandma's "waxing" machine that sat in her closet next to the vacuum cleaner? That thing that our PARENTS tried DESPERATELY to avoid owning? Right. You will need one of those (or something like it).

I would rather have a high end porcelain tile that LOOKS like brick. Brick is WAAAAAAAY too much work for lazy ol' me.

What's even worse than the "waxing machine" is the self polishing wax...like mop and shine....which sealed the dirt in with a coat of varnish like stuff. I have a quarry tile floor in the solarium that was treated that way. Ammonia and a brush got it off but it was an awful job!
Don't use vinegar....it will do a number on the grout.
Beautiful floor by the way!