On Fri, 20 Oct 2017 09:05:51 -0400
Ed Pawlowski wrote:

standing on concrete. Mats made for standing help too, of course.

i used some retired bath mats made from some kind of soft plastic
that also had suction cups and over that i used a plastic carpet
runner with the grippy points on the bottom

it worked fine but in a recent cleaning i noticed that the bath mat
had started to react with the concrete

the mat left a stain on the concrete and the entire mat changed color

it got darker

the carpet runner did not change at all

i tossed the bath mat