Technically speaking, blowing compressed air through any fuel tank will, at some point, bring the fuel/air ratio into the 'scary' zone and is the wrong approach...as near as I recall.
As was mentioned earlier, a fuel rich environment is relatively safe as is a oxygen rich one, but if you start to mix it up with compressed air, or air movement, you will at some point hit the magic ratio and it could be barbecue time.
Stuart
