Has anyone cleaned out their exhaust and tried to make it back to as new as possible? What about the catalytic converters or high flow cats?

What cleaning solution did you use for the inside carbon deposits and whatnot?

Were you able to successfully clean out your resonator/muffler?

I feel like cleaning the insides, especially resonator/muffler material and catalytic converter material will make the exhaust perform closer to 100. Thereby reducing/affecting sound or even flow of the exhaust gases.

Thoughts?