title_body: Home roaster cleaning and/or seasoning
upvoted_answer: The roasting chamber of your Gene Cafe is made of Pyrex (heat-resistant tempered glass), and leaving the old oils to accumulate and burn will cause the the inside of the drum to turn black. The darker material will likely change your roasting time, and the fouled glass will not allow you to monitor your roasts. Glass does not need "seasoning", so it should be cleaned regularly per the manufacturer's recommendations.  
  
  Seasoning is typically a way to create a stick-resistant coating on a porous metal surface (like cast iron or carbon steel). When a thin layer of fat or oil is heated on these surfaces, it forms a polymer which provides rust protection and creates a non-stick surface that will keep whatever you are cooking/roasting from reacting with the cooking surface (the juju you mentioned above). 
  
  If the roasting chamber were made of cast iron or carbon steel, seasoning would be recommended. But neither glass nor stainless steel need seasoning, and you're just changing the built-in characteristics of your roaster. 
  
  To keep your roaster in optimal roasting condition, keep your glass roasting chamber clean.