Sorry if I repeat anything that was already said. I just skimmed everyone’s posts.
Yes, remove nests after it’s used. It’s best for the bluebirds. Gets rid of any critters living inside and also keeps the nest low in the box. And the bluebirds seem to prefer to make a new nest at least at my house. No need to supply nesting material. Although sometimes purple Martin landlords sprinkle pinestraw on the ground in case they want to use it. (White soft pine needles)
Like Carol said, put the mealworms in a white or clear glass or smooth plastic small container. Not a large bowl. Something with shorter sides. A glass pie plate might work.put it where they can look down on it. Put it close to where they perch. Use live ones at first so they can see them moving around. It takes a while. You have to be consistent and patient. Then once they find them…move them gradually wherever you want to feed them. Mine is near my back door. After they get hooked you can try the rehydrated ones.
Tammy