pottery, earthenware
缻 centers on fired clay vessels: pottery and earthenware. The two given meanings are essentially the same idea expressed at different levels of specificity.
缻 combines 缶 (a jar or pot) and 瓦 (tile or earthenware), both associated with clay vessels. The character likely reinforces the idea of pottery through two related semantic components.
The left side 缶 is a lidded jar, and the right side 瓦 is a clay tile. Together they form a complete piece of pottery: a fired earthenware vessel.
For カン, imagine a potter shaping a clay can: can -> カン, and the finished piece is a sturdy earthenware jar.