كَانَ صَاحِبُ الْبَيْتِ كَثِيرَ الرَّمَادِ.
The householder had much ash—a traditional allusion to frequent cooking and hospitality.
The traditional association moves from abundant ash to frequent cooking for guests and then to generosity. A literal abundance of ash remains conceivable, which helps explain the kināyah mechanism.
For an audience unfamiliar with ash from cooking fires, the allusion may fail. Rhetorical interpretation involves conventional cultural knowledge as well as semantic possibility.