"Naval jelly" rust dissolver is sold at many places like Home Depot in the USA in the paint department and most auto stores that sell body work stuff.

It is made by the Loctite corporation. north America group, Rocky Hill, CT 06067 and Mississauga, Ontario, CANADA

Of course you need to remove rust as much as you can with a scraper, wire brush or sandpaper wheel but with several applications (and in some cases only one) will eat rust down to the metal.

You'' find it. great product. Just be patient and do more prep than you think you will need to then look again for more rust. On my bumper hitch , at least 5 times when I thought AI was done I found more rust. I guess the naval jelly loosened stuff I did not see with the bare eye.

William
Vanagon site http://members.home.net/holisticdream/vanagon1989.htm 
Holistic Health Center site http://members.home.net/wholehealthfound/welcome.html 

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