Chayei Sara

If (24,31) Lot cleaned out his house from Avoda Zara for Eliezer (because he knows Eliezer can't stand it) why does he(Chizkuni-24,32) say Eliezer must wash his feet off from Avoda Zara (since Lot didnt want any Avoda Zara other than his own in his house)? He knows that Eliezer hates Avoda Zara and would never worship the dust on his feet!