Farmfresh
City Biddy
No idea if this works at all, but Grandma Nettie used to always put any morels that we found in a bowl of cool water and let them soak for a few minutes, swishing them occasionally. She said this drove out any hiding bugs AND washed the spore into the water. After the swishing she always poured the water around the trees in the yard. She claimed that would seed the spores for more mushrooms.