saltiness
鹸 centers on saltiness, the sharp, mineral taste of salt.
鹸 combines the salt radical 鹵 with the phonetic component 㑒, suggesting a character related to saltiness with a sound contribution from 㑒.
The left side 鹵 is the salt radical, and the right side 㑒 looks like a person tasting something. Imagine someone sampling a pinch of salt and puckering at the saltiness.
For ケン, picture a can of salt: can -> ケン, and the saltiness fills the can.
soap
potash soap
saponated cresol solution
toilet soap
bar soap; solid soap
liquid soap
foam soap
laundry soap; detergent
liquid soap
soapsuds; lather
soap dish or box
soap works
soapy water
soap ball
soap-dish
soap dish or box
soap dish or box
soapmaking
green soap; medicinal soft soap
medicinal soap