If you are looking to get some Dinitrol inside your sills, bear in mind that if you pull the plastic door plates off the car door sill you will see four holes you can squirt the stuff into. It looks to me like the sills have a third metal skin between the outer and inner skins. The door plates can be removed with a screwdriver carefully pushed underneath them to pry them up. There are three plastic attachments which push into three of the revealed holes. You might want to wrap something over the end of the screwdriver to protect the paint.
Hey, thanks for the advice Shane. This is a job I need to do as I can see some nasty reddish discolouration creeping out from beneath those plastic door plates. That's one more job added to the summer 'to do' list!
It was exactly the same thing that led me to have a look. I have some places where the plastic plate has moved very slightly and worn the paint away leading to rust forming. But generally, I was pleased to see very little real problem under them.
