How to renew shine??

Hi Beverly it does look like you can buff them out and renew them yourself: https://www.knbcabinet.com/how-to-revitalize-corian-countertops/

You can use a commercial countertop polish like Rejuvenate Countertop Polish.

A few ways

https://www.doityourself.com/stry/how-to-clean-and-refinish-a-corian-countertop

https://blog.solidsurface.com/clean-refinish-corian-solid-surface-countertops/

https://www.youtube.com/watch?v=JlASQQMlnDw

Here is what the manufacturer recommends.

http://www.corian.com/-use-care-

• Use a commercial countertop polish on your Corian countertop to make its surface shiny and new. You can also use polishes made for other types of countertops, such as granite, on your Corian countertops.
• Generously spread the polish onto the countertop in circular motions using a clean microfiber cloth. Take a small amount of the polish on a piece of microfiber cloth. Wipe it onto the Corian countertop in circular motions, reversing the direction of motion after every 3-4 rotation. Then buff of the polish with another microfiber cloth.

If your Corian countertops are too old and damaged to revitalize and get the shine back yourself, then you can get professional countertop refinishing.

Hope this helps you:

https://www.wikihow.com/Polish-Corian-Countertops

Here's a post that might help you - https://www.knbcabinet.com/how-to-revitalize-corian-countertops/#:~:text=Use%20a%20commercial%20countertop%20polish%20on%20your%20Corian%20countertop%20to,using%20a%20clean%20microfiber%20cloth.

Hi Beverly, hope this helps you out,

https://www.wikihow.com/Polish-Corian-Countertops

And, be careful as to how you clean your corian. That may be part of the problem as to why they are not as glossy as you would like. Follow maufacturers recommendations for best results.

Hi! Check the manufacturer website for recommendations.

You can use a hand polishers and some polishing compound.