A little less "effort" to accomplish the same thing Lynn (LATECH) is talking about... remove the 1/4 NPT plugs on both sides of the block near the pan "rails". This will drain the coolant from the block entirely. They generally have a 9/16" "head".
Some "buddies" may suggest using a ScotchBrite pad on a right-angle grinder to remove the gasket material. DO NOT DO IT!!! The flat scraper is the best way. Follow it up with a light "dusting" with a medium or coarse wire wheel (cup). Many line mechanics use the ScotchBrite stuff. We ineveitably have to mill an "extra" .005" off a head due to the rounded edges and uneven "plane" they leave behind. If you see a "spark" fly off, it isn't ScotchBrite. It's iron... They do even more unapparent damage to aluminum.