Like MaryMary, I let some of our houseplants stay outside for our spring/summer/early autumn, then bring them in. The ones that are small enough I simply dunk in a bucket of tepid soapy (soap, not detergent) water, and after about five minutes rinse them off. I put waxed paper or plastic wrap over the soil to keep it from falling out of the pot, turn the plant upside down, and dunk. After the rise I remove the paper or plastic wrap.
Those that are too large (and there are only two big ones, thank heavens) I spray with a soapy solution on both sides of the leaves and on the stems also, then rinse with plain water after about five minutes. I don't bother with covering the soil since none is going to fall.