On 3/29/2019 10:22 AM, condo owner wrote:
Here's a photo of the rubber tiles when they were new (8 years ago):

https://st.hzcdn.com/simgstmp/1ce0d7...29cd_tmp-9486/



They looked nice when new. Looking at how many and the way they
discolored, it is probably something in the mix, not the surface. Have
you tried scraping a spot? In a corner take a knife and scrape about
1/32 off and see if it is black or mixed with the discoloration.