I use Simple Green. It is environmentally safe (good for all the tree huggers) and cuts right through the grease. As Wayne said that grease can get rancid and does contribute to the nasty odor. My Dera gets quite smelly because I do use a tarp to cover it when it is not in use to prevent rust.
Just clean it out after every two cooking sessions and re-season.
Big Boy Jerky
Authentic Hardwood Smoked Jerky
Family BBQ and Catering
~: Proud Bandera Owner :~