rechromed bumpers

I have had my front and back bumpers rechromed and they tell me to tremclad the back surface to keep them from rusting???????
Anyone else done this or know??
I never heard of this before!

I had the ones for my '70 Challenger rechromed about 4 years ago. Other than washing it never sees water. I havent done anything special to them and they havent rusted. Not really sure what to tell ya. Maybe use rustoleum or some other rust preventive paint on the back side thats natural or silver in color. Eastwood may have something that would work.