wash
澣 centers on cleansing with water: washing or rinsing something clean.
澣 combines 氵 (water) with 幹, which likely contributes the sound カン and may also carry a sense of 'main part' or 'trunk', but the exact historical development is uncertain.
Water 氵 pours over the right side 幹, like washing the trunk of a tree or the main part of something until it is clean.
For カン, imagine washing a can of paint under running water: can -> カン, and the water cleans the can.