If you're still worried about run off--onto your grass or down a storm drain, try using one of those kiddie plastic pools under your truck to catch the water and grease/crud. Let the water evaporate and dispose of the waste appropriately, possibly with your used engine oil. I've been thinking of doing it this way since most coin-op car wash places do not allow engine degreasing. If the pool is too tall, you could always cut it down. Not the most manlyest of colors, but they are cheap and disposable.

Ed

 

I've found another product that works pretty well. Its made by pennzoil, and its called "Steam Premium". It comes in a big 22oz can, and one is enough to do the job. I've never had any luck with the Gunk stuff, but this seems to work pretty well.

 

Here's a tip for this nasty job. If you have a house, hook up a hose to the hot water heater tank. There's a valve at the bottom that will accept a hose. The hot water works better. Kind of a poor man's steam cleaner. Make sure you use gloves though, the hose gets hot pretty quick.