Waffle pad left imprint on black slate floor. What can I try?

[Mabo]

Hi All, I put down a small rug on a rubber(ish) waffle pad on top of our black cleft slate floor. I pulled up the rug today and saw that it already left a waffle pattern on the stone. It's only been about a month. I have so far tried Dawn, baking soda poultice (18 hours), ammonia, and good old scrubbing. Nothing seems to make a difference. The marks are actually more noticeable when wet. Attached are pictures of the floor dry and wet. In the wet picture you can actually clearly tell where the pad ended. I suspect that the darker marks are where the contact points were. What can I try to remove these marks?

 

[Qwerty]

@Lithofin BOB ....... he may be of assistance

 

[Dumbo]

I doubt rubber has damaged slate so probably requires stripping and resealing but as @Plan Tec Tiling says @Lithofin BOB is the man who will know if anyone will .