The plant lives by using photosynthesis to produce sugars and starches. If the leaves are clogged with dust, less sunlight gets through, slowing the process down and affecting growth. Smooth leaves should be wiped with a very soft cloth or a sponge dipped in soapy water to get rid of the build-up, while hairy leaves should be brushed with a soft brush.
Small plants can be carefully inverted in to a bucket of water for a few minutes and then left to drain. Leaving old flowers on the plant can encourage mold, so they should be removed as they fade, as should brown leaves.
Any leaves that fall should be removed from the surface of the soil before they start to decay. Trim any stems which have died back after pruning to avoid leaving disease-prone stubs.
“Dust that builds up on leaf surfaces should be removed regularly using a soft cloth, sponge, or leaf wipe.”