I have a Zephr Venezia 42" range hood with mesh filters that is about 7 years old. Though I have cleaned the filters and wiped down the housing, there is still a grease smell. I can see grease build up on the fan blades. I have seen YouTube videos on removing the fan blades for cleaning for other brands, but not Zephr. Zephr's response to me was "hire someone". It is not discussed in their manual. Does anyone have experience with this problem?