Can any outdoor furniture be safely pressure washed?
Generally speaking, yes, if done by an expert. This includes any plastic, metal, wicker or wood. While e.g. glass table tops would be washed by hand, all metal or wood frames can be safely cleaned with a pressure washer.
If you want to give it a try yourself, then watch these short videos on my website:
Knowing how-to clean your outdoor furniture
Different types of outdoor furniture being effectively pressure cleaned by laymen and professionals!