Does the container have to be washed or rinsed off in between emptying and refilling? Is so, is regular soap and water okay or should I stick to more natural ways of cleaning (i.e. Vinegar/water mix)?
If you are going to immediately start refilling your bokashi bucket, then a quick rinse and spray down with the hose is all the bucket needs between emptying and refilling. If the emptied bokashi bucket may sit for a few days before being refilled, then a slightly more thorough clean is needed. But don’t use any harsh chemicals; warm water and an old rag normally does the trick.
From time to time you may notice persistent odors in your empty bucket. If this happens, simply sit the open bucket in the sun for a while; sunlight is a fantastic disinfectant.