What is best for this rust +plastic trim clips (discussion)

[Stand-in]

I have no idea the best way to deal with this rust and I am currently winter proofing the car (only the battery tray, trunk and a few spots in the sill and then this fecker need attention). I would be remiss to just spray rust converter in there right?

And then I also had to remove the trim piece near the sill to get access to the seat mounts(had to weld them back into shape) and the rust behind the door seal. Luckily the trim channels for the clips to reside in are fine, but alas only one came out with the trim. When I try to pull them out they seem to just bend.... I have used plyers, trim removal tools, but all I can think of right now is to drill them out and buy a replacement trim part. Any ideas?

[Jeroen]

I'm no specialist when it comes to rust proofing, but for the trim clips: they do come out with fork shaped clip removers. To make sure the fit and function correctly, replace all of them, for both inner and outer sill covers. They cost peanuts afaik.