Mastic Remover for Concrete Surfaces

We had 66-year-old black tar mastic that had to be removed. After watching the video this product looked to be the best option, perhaps it was, but it was not a simple or easy job. It took almost three times (3X) the amount of oil to do the job as the coverage estimate specified. For me that meant 3 buckets and it split my job up over 3+ weeks. I did the job in three sections. For the first section I put the oil on thick and left it in place for 18 hours, I then spent hours scraping until the oil was approaching tar status and then I took it up using kitty litter and a shovel. I did this process twice more (not for as many hours) before I had a relatively clean slab. I did a thin forth coat before I considered the section done. The oil leaked under the wall footers to our front porch area onto my new colored pavers and into an adjoining room discoloring the travertine tile. I had to repeat this process for the other two sections. I do not think there was any visible difference between leaving the oil on fo 18 hours versus 4-6 hours. We used a lot more kitty litter to keep the oil from leaking out of the confined space. The floor still has black spots, the gap under the drywall looks nasty and the stuff is near impossible to get off fabric or boots. Since the new floor is not going in until we finish refreshing the drywall and painting we chose to purchase a rug remanent for $200 to avoid looking at and walking on the slab/residual tar. For us, this was a VERY manually intensive job that took a really long time and was incredibly messy. The results are good enough to put down a wood sub-floor, and that is what we need, so I guess the product worked, but I would not do it as a DYI job again. I doubt we saved any money either.