Leaking cap

I have a cap on the end of a pipe that is leaking. It is rusted and corroded which is what is causing the leak. When I go to replace the cap I know to turn the water off and turn on several faucets to drain the pipes. When I am removing the cap I will use a pipe wrench on the cap and another wrench on the copper fitting to make sure it doesn't twist off as well.
Is there something else I should be aware of?
I have a 5 gallon bucket there right now it's dripping into and to catch any access water once I start taking the cap off. Should I clean the threads before putting the new cap on? Would a wire brush be sufficient for that?

Wire brush should be fine

When you replace the cap use a brass one.

Use heat and pull off the copper make adaptor. Sweat in a cap or a sillcock if you have use for acfaucet there.