How do I know if old leaf springs are still good?

[Lonesome7.3]

I am thinking about using a set of stock leaf springs on my 96 F350. The problem is they came out of a beat to hell donor truck and I am not sure if they are still good. I do have an add-a-leaf kit sitting on a shelf I am thinking about using with them. But how do I find out if they can still hold the weight of that Power Stroke? I do plan to strip them down to bare metal and look for cracks, but what else can I do to make sure they are still serviceable?

 

[foxman]

After you strip them down to just the spring pac, you can take them to a place called Columbus Spring where they can tell you anything you want to know about them.
Foxman

 

[Lonesome7.3]

I did not know there was a spring place around here. Thanks!

 

[Diesel_brad]

Chances are, if the truck has over 100k and 13 years old, they are worn out

 

[Lonesome7.3]

The gauge cluster was missing beifre I got the truck. But, by the looks of it I would say it had at least that many miles.