Keeping it clean

How is it possible, for the last few months I have been chucking a Bulldozer or a backhoe on the back of my truck sometimes both and doing about 120 k's, to the back of my daughter and son in-law's farm, doing a few jobs for them, as you do with daughters, 100k's of good tar seal and 20 Ks of dirt, giving the truck a quick hit with the hose when I get home. I have just spent 6 hours give the truck a decent clean up and it looks sort of OK, but every trip I see the logging trucks coming out of the bush spotless without a speck of dust, how is that possible, is there always a portable truck wash just 100 yards into the bush, is there something I don't know. 

They might be running positive earth n acting as a dust repellant

LOL
Can I have one th@ cobba's drinkin
LOL
cya

Any time Swishy, our water is of high quality up here unlike what we experienced at Quorn SA.