I have restored the battery box and front fenders and undercoating.  It was the same process used on the floors. 

I'll let the pictures speak for themselves. 

Here is my 6 volt lead-acid battery-  Not a fake cover over a modern battery.

Yes, tar paper strips were stock on the battery box floor.  Check the parts manual and you'll see them there.

Cleaned and restored all the nuts and bolts, horns, turn signals and fog lights.  Even spent time to clean the wires.

I used the same process as when I restored the original floors in the car.  I will greatly simplify it in my description in this section.

Basically below are three shots.  One before, one during, and one after in the fender well.  The work performed was done the same way as for the floors and as described in the Floor Restoration section.  Please read that section for LOTS of detail.  In short- I removed the undercoating, cleaned and metal prepped the bare metal surface, and then applied the same products as described in the other section.  It required a lot of man-hours in the fenders and battery box to get it all right.  Here are the three shots:

Before:

During:

After: