See if these help you.
Hi Joan, is it the fan blades you want to clean or the filter? Here is some instruction to guide you, hope it helps!
And the fan itself
Hello. Are you asking about the exhaust fan above your cooktop or an interior fan in a convection oven?
Are you asking how to clean your hood vent? If so,
Perhaps this will help:
Joan: I just take a degreaser to the fan -- and put the filter in the dishwasher!
If you are referring to a conventional fan/light combination hood above the stove, the filters can be removed, and either washed in the dishwasher, or scrubbed by hand with a good grease removing soap. Turn off the breaker to the unit before cleaning the inside of the hood to avoid any potential electrical shocks from water touching electric parts.