Garage Floor Cleaning Advice Needed

[HighTide]

These pictures show a garage floor under a condo building built in 1984. The HOA is interested in getting the concrete back to original if possible. If they can't, they are seeking advice on how to make this garage look better. The HOA is not sure what has been done to it in the past that made it look like this. There are around 20 parking spaces in this garage. Can anyone determine from the pics what was done to make it look like this? What advice would you give the HOA? Thanks!

 

[extremecleantn]

I would clean it with a good degreaser first with hot water to remove as mush as possible then follow up with the bt200. I personally have not had much luck with the bt200 with motor oil but others say they have just make sure to let it set for several days they wash. You can contact Paul I know that he has the bt200 at a good price.

 

[HighTide]

Despite it's look, there is very little if any oil on the surface. The glossy black sections isn't oil. Could this have had some sort of black sealer put on it years ago with maybe a poorly done acid wash since?

 

[extremecleantn]

That is really hard to tell from the photo, have you tried to take a knife and scrap it to see if any comes up? It looks like in the photo there is residue on the concrete, you need to make sure someone didn't leave any chemicals there that have dried up, then when get wet they can burn someone.