I'm stripping to the metal. Some of the old bond has chips and imperfections in it. Can I add new bondo to this or does all the old bondo have to come out?

remove all of the old filler in my opinion, youm have no idea if any corrosion issues exhist below the old filler. I wouldn't want to finish up and see bubbles appear. Bob

Without a doubt, remove all of the old filler. Has anyone used the latest evercoat "Rage Extreme"? I just bought some and it seems to be the best I have used yet!

Rage xtreme graemlins/thumbsup.gif sweet product.

Well worth the cash