damaged activa pirelli rubber tiles

We just finished a kitchen renovation that included installing new, slate-colored pirelli rubber tiles (the studded ones that have raised dots) for the flooring. Here’s the problem: Our contractor didn’t do the cleanest, most meticulous job. We found dried glue between two tiles. Then we were doofuses and tried to take it off by rubbing it with the rough side of a sponge. Now it looks like we may have scraped away the shine in that area. Does anyone know what product we should use to get the luster back? h