On the 98 I got a few months ago, the thin strip between rear doors and the rear wheels had some serious rust bubbles.

I used a grinder with a wire brush attachment and was able to clean away the rust, although I have some fairly large holes that will have to be repaired.

I've used small brushes to get everywhere (I mean everywhere) inside body cavity with POR-15 which should seal in any remaining rust. However in the course of getting to all the rust, there was some putty or a seal between the two layers of metal that had to be removed to get to all the rust. I should probably caulk that back up before I bondo and was wondering if anyone had any idea what would be the best stuff to use.

 

I should have done more research myself first. I'm looking for seam sealer. I'll pick up some at the auto store tomorrow.