My front door/porch wreath made up of a grapevine wreath and artificial flowers needs cleaning and refreshening.
I'd just lightly hose or off
Canned air like you use for a computer keyboard. On some of mine, I remove the embellishments and hose off the grapevine, let dry in sun then start over. They do sell wreath cleaner at craft and hobby shops, but I have never used them, so can't provide an opinion on effectiveness. You can always hand dust with a paint brush, old tooth brush and a microfiber cloth.
I use my blow dryer to get the dust off. I also have a microfiber duster that "grabs" dust & dirt if just blowing off doesn't work.
Here are some videos for you! Good luck.
I try wiping it down first. Sometimes a good shake helps. If really dirty, I will remove what I can and gently wash them. Air dry and then it may be time to refresh and update.