Has anyone figured out a good way to clean the undercoating on the frame on newer superduties?

 

When I bought my rig a few months back, I saw from the underside the previous owner, like myself, actually uses 4 wheel drive and not just on the pavement! There was quite a bit of dirt built up in areas. I let the sprinkler sit underneath for a while, sprayed some castorol cleaner, let it sit a few and then put the truck up on ramps and pressure washed away. Worked real well and being on the ramps I was able to get to places without laying under the truck. Make sure not to blast away at any crucial areas though and just use a good brush instead.

Regards,
Jeff