Cover the cooking equipment with plastic sheeting. Use plastic sheeting to also protect the floor and any work surfaces beneath the hood. Tape plastic sheeting from the side edges of the hood and let it hang to the floor to create a controlled environment for cleaning. Note that you may need a step stool or ladder to reach the hood.
Remove the filters from the hood. Wipe up excessive, loose grease from the interior of the hood and the removed filters with paper towels or rags.
Fill the steam cleaner tank with water and steam cleaner de-greaser. Affix the hose of the steam cleaner with a scrub brush nozzle. Turn the steam cleaner to low-medium.
Pull the trigger on the handle to release steam and move the nozzle across surfaces in slow, back-and-forth, slightly overlapping motions. Wipe up the loosened grease left behind with paper towels or rags.
Suck up any standing dirty water that forms with a wet/dry shop vacuum.
Replace the de-greasing solution in the steam cleaner with fresh water and spray the hood and filters a second time to rinse the cleaning solution residue or simply wipe down everything with a damp sponge.
Reassemble the hood and clean any messes that were made outside the plastic sheeting.