Step 1. Used blocks

If you're not starting off with a new block obviously you're going to need to thoroughly disassemble your block, including removing the seals with a seal puller, and clean all threads with a tap. Regardless what you read a there's no material removed with standard taps. An air compressor is very important. I degrease the block and scrub it with degreaser using a toothbrush to clean every crevise. I toss the breather and gaskets, Run the large bolts though a die to clean the threads. I do hone the cylinder with fine stones and a hand drill and clean with WD-40. I then use a cylinder brush on the drill and lots of warm soapy water, and also soak the block in warm soapy water. I then blow the block completely dry with compressed air. If you have a NEW block then start at step 4.