There has been considerable efforts in modelling the semantics of Internet of Things and their specific context. Acquiring and managing metadata related to the physical devices and their surrounding environment becomes challenging due to the dynamic nature of environment. This paper focuses on managing metadata for Internet of Things with the help of crowds. Specifically, the paper proposes a collaborative approach for collecting and maintaining metadata through micro tasks that can be performed using variety of platforms e.g. mobiles, laptops, kiosks, etc. The approach allows non-experts to contribute towards metadata management through micro tasks, therefore resulting in reduced cost and time. Applicability of the proposed approach is demonstrated through a use case implementation for managing sensor metadata for energy management in small buildings.