brass wire wheel in die-grinder for head..... brass wont hurt a thing in the cast iron/steel valves.... could prob. clean the piston tops too....pistons look good though...
i use little scuffy wheels in my die grinder to clean all the surfaces when i rebuild bike motors(bike tech) these from harbor freight....
http://www.harborfreight.com/pack-of...scs-99983.html they have a small pack with the arbor etc.... work awesome...
there will be other answers... just how i would do it myself..... good luck with your timing this time thru.....