Nice one. I had a Yoda figure once with a really dirty cloak. I took a small amount of laundry detergent, put on my rubber gloves, filled the sink with cold water (I was concerned about shrinkage and so I did not use hot) and gave it a gentle hand wash. I was amazed at the amount of dirt that came out after a minute of gently squeezing the cloak together repeatedly. After laying it out to dry flat to ensure no wrinkles appeared, and of course ensuring that it was bone dry, I put it back on the figure, and it looked like new!
Your Luke is great, but if you ever wanted to clean the soft goods, I would definitely recommend doing what I did, as they should clean up brilliantly.
Thanks for sharing him
Jeremy