How do I clean this tile?

I have never scrubbed this type of tile before. What is the best method here? Do these tiles have a chance of looking good again or is this how they normally look? Can I use stripper and a black pad to Scrub them? Can I seal them to be more shiny? Any tips would be appreciated!

I have never scrubbed this type of tile before. What is the best method here? Do these tiles have a chance of looking good again or is this how they normally look? Can I use stripper and a black pad to Scrub them? Can I seal them to be more shiny? Any tips would be appreciated!