I clean my plants (all real) one of two ways.
If they're outside for the summer, I have a spray bottle full of water, and just spray the dickens out of them. If we had a garden hose, I'd use that instead. A good rain would also work.
When they're inside for the winter, I just take an hour or so every month-ish and wipe down the leaves with a damp rag. That's also when I go through and get rid of dead leaves, fertilize anything that needs it, etc.