Door Pillar, B pillar??

[wolfthing2000]

I think it is called the B pillar, at any rate it is where the door hinges bolt to.
I was under the truck cutting out a small rusted area at the bottom of the front cab support that goes across to the under side of the pillar and bolts up under there through the inner rocker panel. After I cut out the bottom of the floor brace I was cleaning out the sound metal on the inside and noticed the old ugly bubble of rust on the surface of the inner rocker panel and right between the channel where it bolts up. A telltale sign of trouble on the other side!!
I poked around there with a screwdriver long enough to brake through and Holy Cow the dirt and old mud and flaky rust that came out would have filled up a beer can ( I measure a lot of things with this world wide standard that doesn't have to be English or Metric, we just all KNOW how much a beer can amount is!!!)
Question is, where does this dirt get in there from and how do I prevent future accumilation there to avoid future problems ( there is a fair amount of cancer removal and repair ahead in this area and the inner kick panel)??
I seem to remember a photo on this forum of a truck that was patched up in the kick panel area and it seems like I remember them leaving an opening about 1 inch or so along the bottom where the kick panel meets the floor.

Any thoughts????

[Tx Firefighter]

Hinges bolt to the "A"" pillar. The latch is on the "B" pillar.

They go in order from front to rear, the windshield always being "A". Some cars have several pillars aft of the the "B" pillar even.

[70GMCer]

Would that dirt and such come from the cowl vent and run into the area you are talking about?

[wolfthing2000]

I am thinking the cowl vent. Does anyone have or know of the picture with the kick panel repair that left the bottom open for clean out I assume????