[amsat-bb] ground rod/plate bonding question

Hello!

I am going to install a large brass plate at the cable entrance to my shack. I have a large ground rod outside the entrance where everything is going to be grounded. I'm planning on using a large piece of copper strap to connect the plate to the rod.

Is there any substance I can use to clean/prep the copper and the brass? Is there a material to use between the two metals to keep them from oxidizing and keep the bond in good condition?

Thanks

Tyler KM3G