The cleaning solution I use consists of white vinegar and water. The formula is one part white vinegar to two parts warm water mixed together in a spray bottle.
I like to take the trees outside and give them a good spraying, but I want them to dry quickly, so I don't want to get the pots wet.
I started by taking one of my smaller trees to my porch. I wanted to be able to lean it against the railing so it would drip dry and so the water wouldn't run into the pot.
I leaned it over the railing and sprayed the vinegar/water solution onto the dusty leaves.
While the first tree dripped, I brought out the next dusty one and repeated the process.
By the time I brought this third tree out, the first one was already dry and ready to take back inside. They dry very quickly and look so nice and clean after being sprayed with this solution. My ficus trees now look clean and fresh with far less effort than it previously took to clean them.