A quick shower can be very beneficial to indoor plants. Source: hnczcyw.com
Dust, dirt and cooking oils that accumulate on the leaves of houseplants significantly reduce the light that reaches their cells and also cuts back on their respiration. A monthly shower with tepid water, either in the sink for small plants or right in the shower stall for taller ones, helps clean the leaves …and may well remove a few insects that might be hiding among the leaves.
To keep the soil of your houseplants from washing down the drain while you rinse them, simply cover it with a piece of cloth.
It’s best to give plants their shower in the morning so the leaves will have time to dry out before night. This is especially true of hairy-leaved plants, as their leaves are slower to dry.