Several advocates of using Cognitive Linguistics insights in second or foreign language teaching have suggested that learners can be helped to interpret unfamiliar idioms by making them aware of the conceptual metaphors (CM) and conceptual metonymies they instantiate. One of the reasons for introducing such CM-guided idiom interpretation is that it is likely to induce cognitive involvement on the part of the learners, and this is believed to be beneficial for retention. In the present study, we first assess whether CM clues given in connection with particular idioms are indeed helpful for students to arrive at correct interpretations. We then evaluate whether raising students' awareness of CMs in connection with some idioms also helps students interpret other idioms, without explicit CM guidance. We pinpoint some of the obstacles to learner-independent idiom interpretation which a heightened awareness of CMs alone seems unable to overcome. Special attention is given to obstacles thrown up by cross-linguistic and cross-cultural differences. To illustrate how cross-cultural differences can hinder adequate idiom interpretation, we analyse the interpretations by 40 Taiwanese learners of English idioms that instantiate the western dualities of mind vs. body and of mind vs. heart. Mandarin Chinese (i.e., our respondents' L1) does not share these dualities with English. (Ying-Hsueh Hu and Yu-Ying Fong)