Hello, I have a 99 Ram 1500. Both of the doors are showing rust at the very bottom. I would say about a 1 inch strip accross the bottom of the doors. It appears to just be surface rust at a glance, but after looking at it further there are small pieces rusting off. How can I fix this problem before its gets worse? I'm afraid if i start sanding i will take off part of the bottom of the door. Any suggestions? I live in the Northeast so rust is always an issue.

Thanks!