Former autobody and paint guy, just finished the annual do it yourself rustproofing on our 2006 Pontiac Wave 5 dr. I know this has been discussed before, but it's a good time to remind people to get those lower front fenders cleaned out...they sure accumulate a pile of crap over a year.
Take the lower rear screws and retaining clips out of the fender liner.
See if anything is growing in there!
Clean it up really good. You may have to take the lower bolt out that holds the fender to the rocker panel. Spray all kinds of oil based rustproofing in there! Take out the plug to access the inner rocker panel and spray a bunch in there too! Remember to do it again next year.