I think ultrasonic cleaners, and moreso heated ones, can aerosolize whatever liquid is in them and flash off solvents. So, maybe a little careful indoors? When they are run with covers, you may see significant droplets form on the under side. I think most that use a beaker or jar might do it to decrease the volume of cleaner needed and just run water in the tank, maybe with some sort of loose fitting cover on the jar? And, maybe careful with decent gun cleaning solvents, they might go after plastic baskets and other trim on the unit, maybe. Good luck with it.