Different painters use different terms, but around here pickeling, whitewashing and milkwash are all about the same with the exception that some pickeling companies make there product in different shades. It is very popular here in TX, I paint new homes often and most go with the milkwash(pickeling). Milkwash and pickeling are applied to the bare wood, then sealed and finished where as whitewash is applied after sealing and sanding the wood, then finished out. the milk and pickel actually stain the wood, the whitewash gives the sealed wood a dusty appearance. If you are going to do this, post back and I can give you detailed instructions and tips, as well how to make your own pickeling. I will tell you know, this is a more advanced technic then painting and staining and takes a little more skill and patience. I only let the best in my group milkwash, but we also have to please the customer(which are usually very picky about there new big home)But a person with enough incentive is perfectly capible of doing it.