My bees are spoiled. I like to try to help them keep clean. I haven't had a hive leave me yet! (bad reference to CCD - beekeeper humor) These boxes, bottom boards, and covers are cycling through for WASHING, SCRAPING, PAINTING...and most importantly SCORCHING. I'll take a propane torch to the insides of these....doesn't hurt - I guess the theory is to burn out any nosema spores, etc.
I have one hive left on the "beehouse" deck to change over to "fresh" outsides. Then I have plenty of fresh equipment for the two packages coming in the mail...and swarm catch or two.
Moving all the frames into "new" boxes also lets you leave behind a lot of the old boxes sticky propolis "issues". And it lets you get a real good look at every frame as they go into the new box.