I just now saw this thread. I did a short presentation on sanitation for my bee club at our last meeting. That meeting was online.
To clean the built up propolis and wax off hive tools I first use one hive tool to scrape the other hive tool. This will remove large chunks of propolis, especially if the hive tool is cold. Then I use scrubbing powder and a green scrubbing pad. That will get all of it off. I follow up with a quick soaking in bleach water. 4 tsp. of bleach per quart of water will do. Rinse and dry. Your hive tools will be cleaned and sanitized.
Other methods to keep brood diseases down include throwing them in a smoker that has a big flames, propane torch, bucket of bleach water (throw tools in the bucket in between apiaries), and even wiping your tools with Clorox Wipes in between colonies.