Intake Valve cleaning - Direct injected Petrol engines

[happy1]

Hi,
Looks like Ford have patented something that other manufacturers are struggling with in their latest direct injected engines: Washing away Carbon build-up on the intake valves by tweaking the camshaft timing.

https://www.google.com/patents/US7137377

For example BMW have developed procedures for scheduled Walnut-shell blasting of the intake valves on their engines with a dedicated blasting adapter.

Does anyone know where I can purchase a bag of Walnut shell grit? (for one of my non-Ford rides)

Cheers,