To clean up the carbon build-up off of the pistons, you can use a brass brush and some solvent. Brass won't scratch steel and does a great job at removing carbon deposits on the piston crowns. Solvents such as "Simple Green" are great for basic degreasing.
If you want to get it looking like new again, you can use a harsh solvent such as Acetone, Paint Thinner, or Kerosene. This requires removing the pistons and letting them soak in the solvent of choice over night.
Monday, September 7th, 2009 AT 4:34 PM