misskriss,
Just my .02 cents but where ever you heard about the truck wash I would imagine this is what they meant. First , there are different types of "coverings and coatings" on mobile homes. Any vinyl or aluminum sided homes(just like any other homes) you can use the above mentioned. However , just like gutters , there are some older mobile homes with the same surfaces in these cases bleach and cold water will not do the trick. Many chemical companies will sell there truck washes for gutter cleaning. The same principal applies here as with gutters, you won't get gutters clean with cold water and bleach.You do want to be careful on the surfaces to which you are applying the chem though. In these cases hot water and the "truck wash" will get rid of the black rain stains on the mobile home or trailer.The key is knowing the difference between the ones with the "baked on paint" , aluminum , or vinyl sided covering. We have 3 accounts with mobile homes and this is from my experiences. I hope I have helped.