Rust!

So, under my rear window seal on my 85 was a patch of rust that started to show at the edge of the seal.

After removal I found bumped up worm like stretches along the bottom where the seal covers the metal.

So, How would you approach this problem? 

How to remove the rust and then what products for remediation? 

All suggestions for how to approach it and what products is greatly appreciated.

Eric 
85 GL auto westfalia