What to do or use to clean up carbon build up?

[chi123]

What's going on everyone? I recently bought a high mileage S4, 85K to be exact, as a daily driver. The car should see less than 5K a year hence why I felt it was okay to buy a car with this high miles. The car has been great so far and running smoothly. I've changed out all the filters, oil, spark plugs, etc on the car already but want the thing to run as good as new. On my other car, it has port and direct injection but the S4 only has direct injection so I know it might run into carbon build up. At 85K, I think it might be a good time to clean up the carbon on the valves and ports but was wondering what do you guys (who have done so or might know how) what to use to clean it up. I know there's different ways as people on the BMW forums with N54 engines use mediums such as walnut shells to clean up the valves and ports. Others use cleaners in the intake manifold. What do most people with B8's use and what do dealers do when they "clean" carbon?

[DGVR6]

Im not sure what the dealers use.. I know people just use chemicals on here to clean it up.
I'll be going the walnut route but im at 22k so I have a while to go.

There is a DIY on removing the supercharger if you search for the thermostat DIY.
From there on its just a matter of rotating the crank and closing off the cylinders while you work on one.
I havnt removed the supercharger yet so if anyone has please chime in. Im pretty sure that's all you need to remove to get to the banks.

[shadycrew31]

I'll be using throttle body cleaner and various wire brushes with a shop vac hooked up to remove all the hard particles.

[Ryan_qttro]

Our dealer uses a kit from BG
We get as many cylinders intake valves closed at one time.
Pour in step 1 Chemical, cover the valves, let us sit for awhile. Suck liquid out, then use a pick to knock loosened carbon off. Put another liquid cleaner in that comes in kit. Clean intake valves off again. Put 3rd bottle in gas tank to help clean injector tips.