how do i deep clean dishwasher without making a mess?

start with the filter, that's where the smell and most of the gunk lives. on most machines it twists out from the bottom under the lower spray arm. scrub it in the sink with dish soap and an old toothbrush. then wipe the door seal and the bottom edge of the door, which never gets washed by the cycle. poke any blocked holes in the spray arms clear with a toothpick. last, put a cup of white vinegar upright on the top rack and run the hottest empty cycle. lay a towel on the floor in front before you pull the filter and none of it ends up on the kitchen floor.