I would for sure be that rookie who is paralysed with indecision over whether to read "clean" as an adjective or an imperative. Is it telling me that it's clean or that it needs cleaning?
Given "dirty" would make a strange (although valid) imperative, it would likely be referring to the state of the dishes
Given "dirty" would make a strange (although valid) imperative, it would likely be referring to the state of the dishes