I centrifuge at around 160 degrees for 6 hours. I have a closed barrel with 2 small vents. And I found about a 1/4 inch of crap on the top of the inside. My question is: when you centrifuge, is the top open or do you have a closed like I do?? I would have a completely open but was concerned in TX that the humidity may get into the heated oil. Any truth to this??

I presume that you are referring to a Dieselcraft CF setup ( like Sunswizard's recommended configuration ) . Use it with an open top . You need exposed surface area for evaporation . Humidity wont get in the oil at 160 deg F . Insulate the barrel too.

Open top or add a fan. Humidity won't get into the VO, but it doesn't flash evaporate as fast in high humidity.

i have small 110v fans on my drum top
I CF at a temp higher than 212 degrees to ensure water is removed.
I capture the CF output then pan test in a cast iron pan.
pratically guarantees you will have no water. Assuming you settle for one month before processing...