I did my cars first carbon cleaning at 83k miles over the weekend, surprisingly the car had very little build up. Looks like once a day WOT does keep carbon away.
Even with the minimal build up gone the car feels much more smoother when revving the engine, and cold starts are quieter and more smooth now. Even removing minimal build up makes a difference. I used CRC valve cleaner to soak the carbon before blasting the valves with walnuts, this CRC stuff make the build up so soft and easy to remove.
https://www.amazon.com/CRC-05319-Intake-Valve-Cleaner/dp/B00PHNQKR2
That's good to know that it does actually cut into it