Used Shortblock Prep

You guys are all crazy, WD40 in a bowl if the piston is out of the block, stick it up side down over night and pull it out and wipe it clean with a rag. if it's in the block soak rags in WD40 and stick in the bores and let it soak, you can wipe it off with a rag. Cleaning throttle blades in throttle bodys same way, in a couple hours the throttle plate is clean. I do it all the time.