So I have a client who does not like the brown spots showing up on her terrazzo floor. 

Would you suggest dropping down to metals and transition to resins? What are the chances of getting these brown areas out? 

This floor is over 60.years old and was waxed maybe 40 years ago. 

We started with 100-200-400-polish because she does not want a very high gloss. She likes the shine level but hates the browning areas especially along metal strips.