turning the fan?

[X-ray]

You will still get the bad smell because the air that goes in will displace the smelly air out: it has to come out, or else you will be trying to turn your Miggy into an air-compressor.
On my A4kt I have smelly SCSI cables because I once taped them together to make them neater. The adhesive from the tape remained on the cables even after I removed the tape and it smells terrible now. I will have to thoroughly clean them because despite running the case open for a week and blowing all the dust out (even from the PSU which I opened), it still has the same smell, namely that of a camel's armpit.

[X-ray]

Seer is right. That is exactly what happened. The rubber bands dried out then snapped. I found them in the bottom of the case, looking like earthworms that had dried in the sun. What I should have done was get proper cable ties. I might do that once I've finished jerking around moving drives from one controller to another, swapping drive bay positions etc.