Hi Guys, we noticed 484 had a few slightly clogged lower flues when we were going to fire her up so, when we removed the spark arrestor to put on the Draft Fan to start the fire.. we just left the spark arrestor off.. we figured we would let 484 draft with no restrictions to clean out her insides a little.. There was no fear of any fire danger.. We have to do a little repair on her spark arrestor also anyway. But I must say I enjoy running without spark arrestors, the Locomotives sound completely different without them on and you don't get showered with cinders in the Cab as much without the spark arrestors on..