Cleaned bumper and used Mothers' "Back to Black".

 

Big improvement from 10 feet...

I found seafoam works really well for bringing old plastic back to life. seafoam is pure petroleum and plastic is made from petroleum, it works well..

I used that stuff a while ago. It worked well, but faded off shortly after. It didn't go back to how bad it was before, but it wasn't a nice black still. If you add another coat a couple weeks from now, and maybe another one a few weeks after that, it'll look great.

 

I have since spray painted my bumpers with this stuff:

 

 

It's stayed black ever since I put it on. You can pick up a can at Home Depot or Lowe's or another home improvement store for $5 or less. I definitely recommend it.

 

I bet VHT dye would work great for fading black bumpers

I'd go with what JJ421 did, or even use Plasti-dip from a spray can (also available at Home Depot/Lowes). Never had satisfactory results with anything that claims to "restore" plastics.